diff --git a/docs/src/ai-support.md b/docs/src/ai-support.md
index 7fb26f9dc..105b713c1 100644
--- a/docs/src/ai-support.md
+++ b/docs/src/ai-support.md
@@ -64,7 +64,7 @@ one-line summary (here trimmed, and then counted, using Miller itself):
[
{
- "count": 662
+ "count": 664
}
]
diff --git a/docs/src/manpage.md b/docs/src/manpage.md
index 38091ec62..0f6e75a95 100644
--- a/docs/src/manpage.md
+++ b/docs/src/manpage.md
@@ -257,14 +257,14 @@ This is simply a copy of what you should see on running `man mlr` at a command p
null_count os percentile percentiles pow qnorm reduce regextract
regextract_or_else rightpad round roundm rstrip sec2dhms sec2gmt sec2gmtdate
sec2hms sec2localdate sec2localtime select sgn sha1 sha256 sha512 sin sinh
- skewness sort sort_collection splita splitax splitkv splitkvx splitnv splitnvx
- sqrt ssub stat stddev strfntime strfntime_local strftime strftime_local string
- strip strlen strmatch strmatchx strpntime strpntime_local strptime
- strptime_local sub substr substr0 substr1 sum sum2 sum3 sum4 sysntime system
- systime systimeint tan tanh tolower toupper truncate typeof unflatten unformat
- unformatx upntime uptime urand urand32 urandelement urandint urandrange
- utf8_to_latin1 variance version ! != !=~ % & && * ** + - . .* .+ .- ./ / // <
- << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
+ skewness sort sort_collection sparkline splita splitax splitkv splitkvx
+ splitnv splitnvx sqrt ssub stat stddev strfntime strfntime_local strftime
+ strftime_local string strip strlen strmatch strmatchx strpntime
+ strpntime_local strptime strptime_local sub substr substr0 substr1 sum sum2
+ sum3 sum4 sysntime system systime systimeint tan tanh tolower toupper truncate
+ typeof unflatten unformat unformatx upntime uptime urand urand32 urandelement
+ urandint urandrange utf8_to_latin1 variance version ! != !=~ % & && * ** + - .
+ .* .+ .- ./ / // < << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
1mCOMMENTS-IN-DATA FLAGS0m
Miller lets you put comments in your data, such as
@@ -1462,7 +1462,11 @@ This is simply a copy of what you should see on running `man mlr` at a command p
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+ -s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+ With -s, output is one record per value-field, with a sparkline field
+ instead of one record per bin.
1mjson-parse0m
Usage: mlr json-parse [options]
@@ -3284,6 +3288,12 @@ This is simply a copy of what you should see on running `man mlr` at a command p
1msort_collection0m
(class=stats #args=1) This is a helper function for the percentiles function; please see its online help for details.
+ 1msparkline0m
+ (class=stats #args=1) Returns a string of Unicode block characters (one of per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.
+ Examples:
+ sparkline([1,2,3,4,5,6,7,8]) is ""
+ sparkline([3,3,3]) is ""
+
1msplita0m
(class=conversion #args=2) Splits string into array with type inference. First argument is string to split; second is the separator to split on.
Example:
@@ -4062,5 +4072,5 @@ This is simply a copy of what you should see on running `man mlr` at a command p
MIME Type for Comma-Separated Values (CSV) Files, the Miller docsite
https://miller.readthedocs.io
- 2026-07-06 4mMILLER24m(1)
+ 2026-07-07 4mMILLER24m(1)
diff --git a/docs/src/manpage.txt b/docs/src/manpage.txt
index b0d6322ca..56e848bb8 100644
--- a/docs/src/manpage.txt
+++ b/docs/src/manpage.txt
@@ -209,8 +209,8 @@
histogram json-parse json-stringify join label latin1-to-utf8 least-frequent
merge-fields most-frequent nest nothing put regularize remove-empty-columns
rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
- skip-trivial-records sort sort-within-records sparsify split ssub stats1
- stats2 step sub summary surv tac tail tee template top utf8-to-latin1
+ skip-trivial-records sort sort-within-records sparkline sparsify split ssub
+ stats1 stats2 step sub summary surv tac tail tee template top utf8-to-latin1
unflatten uniq unspace unsparsify
1mFUNCTION LIST0m
@@ -236,14 +236,14 @@
null_count os percentile percentiles pow qnorm reduce regextract
regextract_or_else rightpad round roundm rstrip sec2dhms sec2gmt sec2gmtdate
sec2hms sec2localdate sec2localtime select sgn sha1 sha256 sha512 sin sinh
- skewness sort sort_collection splita splitax splitkv splitkvx splitnv splitnvx
- sqrt ssub stat stddev strfntime strfntime_local strftime strftime_local string
- strip strlen strmatch strmatchx strpntime strpntime_local strptime
- strptime_local sub substr substr0 substr1 sum sum2 sum3 sum4 sysntime system
- systime systimeint tan tanh tolower toupper truncate typeof unflatten unformat
- unformatx upntime uptime urand urand32 urandelement urandint urandrange
- utf8_to_latin1 variance version ! != !=~ % & && * ** + - . .* .+ .- ./ / // <
- << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
+ skewness sort sort_collection sparkline splita splitax splitkv splitkvx
+ splitnv splitnvx sqrt ssub stat stddev strfntime strfntime_local strftime
+ strftime_local string strip strlen strmatch strmatchx strpntime
+ strpntime_local strptime strptime_local sub substr substr0 substr1 sum sum2
+ sum3 sum4 sysntime system systime systimeint tan tanh tolower toupper truncate
+ typeof unflatten unformat unformatx upntime uptime urand urand32 urandelement
+ urandint urandrange utf8_to_latin1 variance version ! != !=~ % & && * ** + - .
+ .* .+ .- ./ / // < << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
1mCOMMENTS-IN-DATA FLAGS0m
Miller lets you put comments in your data, such as
@@ -1441,7 +1441,11 @@
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+ -s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+ With -s, output is one record per value-field, with a sparkline field
+ instead of one record per bin.
1mjson-parse0m
Usage: mlr json-parse [options]
@@ -2062,6 +2066,16 @@
-n Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
-h|--help Show this message.
+ 1msparkline0m
+ Usage: mlr sparkline [options]
+ Reduces numeric field(s), across all records in input order, to a compact
+ Unicode sparkline -- one block character per record -- for visualizing
+ trends. Emits one output record per field. Holds all records in memory
+ before producing any output.
+ Options:
+ -f {a,b,c} Field names to sparkline.
+ -h|--help Show this message.
+
1msparsify0m
Usage: mlr sparsify [options]
Unsets fields for which the key is the empty string (or, optionally, another
@@ -3263,6 +3277,12 @@
1msort_collection0m
(class=stats #args=1) This is a helper function for the percentiles function; please see its online help for details.
+ 1msparkline0m
+ (class=stats #args=1) Returns a string of Unicode block characters (one of per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.
+ Examples:
+ sparkline([1,2,3,4,5,6,7,8]) is ""
+ sparkline([3,3,3]) is ""
+
1msplita0m
(class=conversion #args=2) Splits string into array with type inference. First argument is string to split; second is the separator to split on.
Example:
@@ -4041,4 +4061,4 @@
MIME Type for Comma-Separated Values (CSV) Files, the Miller docsite
https://miller.readthedocs.io
- 2026-07-06 4mMILLER24m(1)
+ 2026-07-07 4mMILLER24m(1)
diff --git a/docs/src/reference-dsl-builtin-functions.md b/docs/src/reference-dsl-builtin-functions.md
index c7e684846..c918cb8a5 100644
--- a/docs/src/reference-dsl-builtin-functions.md
+++ b/docs/src/reference-dsl-builtin-functions.md
@@ -59,7 +59,7 @@ Operators are listed here along with functions. In this case, the argument count
* [**Hashing functions**](#hashing-functions): [md5](#md5), [sha1](#sha1), [sha256](#sha256), [sha512](#sha512).
* [**Higher-order-functions functions**](#higher-order-functions-functions): [any](#any), [apply](#apply), [every](#every), [fold](#fold), [reduce](#reduce), [select](#select), [sort](#sort).
* [**Math functions**](#math-functions): [abs](#abs), [acos](#acos), [acosh](#acosh), [asin](#asin), [asinh](#asinh), [atan](#atan), [atan2](#atan2), [atanh](#atanh), [cbrt](#cbrt), [ceil](#ceil), [cos](#cos), [cosh](#cosh), [erf](#erf), [erfc](#erfc), [exp](#exp), [expm1](#expm1), [floor](#floor), [invqnorm](#invqnorm), [log](#log), [log10](#log10), [log1p](#log1p), [logifit](#logifit), [max](#max), [min](#min), [qnorm](#qnorm), [round](#round), [roundm](#roundm), [sgn](#sgn), [sin](#sin), [sinh](#sinh), [sqrt](#sqrt), [tan](#tan), [tanh](#tanh), [urand](#urand), [urand32](#urand32), [urandelement](#urandelement), [urandint](#urandint), [urandrange](#urandrange).
-* [**Stats functions**](#stats-functions): [antimode](#antimode), [count](#count), [distinct_count](#distinct_count), [kurtosis](#kurtosis), [maxlen](#maxlen), [mean](#mean), [meaneb](#meaneb), [median](#median), [minlen](#minlen), [mode](#mode), [null_count](#null_count), [percentile](#percentile), [percentiles](#percentiles), [skewness](#skewness), [sort_collection](#sort_collection), [stddev](#stddev), [sum](#sum), [sum2](#sum2), [sum3](#sum3), [sum4](#sum4), [variance](#variance).
+* [**Stats functions**](#stats-functions): [antimode](#antimode), [count](#count), [distinct_count](#distinct_count), [kurtosis](#kurtosis), [maxlen](#maxlen), [mean](#mean), [meaneb](#meaneb), [median](#median), [minlen](#minlen), [mode](#mode), [null_count](#null_count), [percentile](#percentile), [percentiles](#percentiles), [skewness](#skewness), [sort_collection](#sort_collection), [sparkline](#sparkline), [stddev](#stddev), [sum](#sum), [sum2](#sum2), [sum3](#sum3), [sum4](#sum4), [variance](#variance).
* [**String functions**](#string-functions): [base64_decode](#base64_decode), [base64_encode](#base64_encode), [capitalize](#capitalize), [clean_whitespace](#clean_whitespace), [collapse_whitespace](#collapse_whitespace), [contains](#contains), [format](#format), [gssub](#gssub), [gsub](#gsub), [hex_decode](#hex_decode), [hex_encode](#hex_encode), [index](#index), [latin1_to_utf8](#latin1_to_utf8), [leftpad](#leftpad), [lstrip](#lstrip), [regextract](#regextract), [regextract_or_else](#regextract_or_else), [rightpad](#rightpad), [rstrip](#rstrip), [ssub](#ssub), [strip](#strip), [strlen](#strlen), [strmatch](#strmatch), [strmatchx](#strmatchx), [sub](#sub), [substr](#substr), [substr0](#substr0), [substr1](#substr1), [tolower](#tolower), [toupper](#toupper), [truncate](#truncate), [unformat](#unformat), [unformatx](#unformatx), [utf8_to_latin1](#utf8_to_latin1), [\.](#dot).
* [**System functions**](#system-functions): [exec](#exec), [hostname](#hostname), [next](#next), [os](#os), [stat](#stat), [system](#system), [version](#version).
* [**Time functions**](#time-functions): [dhms2fsec](#dhms2fsec), [dhms2sec](#dhms2sec), [fsec2dhms](#fsec2dhms), [fsec2hms](#fsec2hms), [gmt2localtime](#gmt2localtime), [gmt2nsec](#gmt2nsec), [gmt2sec](#gmt2sec), [hms2fsec](#hms2fsec), [hms2sec](#hms2sec), [localtime2gmt](#localtime2gmt), [localtime2nsec](#localtime2nsec), [localtime2sec](#localtime2sec), [nsec2gmt](#nsec2gmt), [nsec2gmtdate](#nsec2gmtdate), [nsec2localdate](#nsec2localdate), [nsec2localtime](#nsec2localtime), [sec2dhms](#sec2dhms), [sec2gmt](#sec2gmt), [sec2gmtdate](#sec2gmtdate), [sec2hms](#sec2hms), [sec2localdate](#sec2localdate), [sec2localtime](#sec2localtime), [strfntime](#strfntime), [strfntime_local](#strfntime_local), [strftime](#strftime), [strftime_local](#strftime_local), [strpntime](#strpntime), [strpntime_local](#strpntime_local), [strptime](#strptime), [strptime_local](#strptime_local), [sysntime](#sysntime), [systime](#systime), [systimeint](#systimeint), [upntime](#upntime), [uptime](#uptime).
@@ -1156,6 +1156,15 @@ sort_collection (class=stats #args=1) This is a helper function for the percent
+### sparkline
+
+sparkline (class=stats #args=1) Returns a string of Unicode block characters (one of ▁▂▃▄▅▆▇█ per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.
+Examples:
+sparkline([1,2,3,4,5,6,7,8]) is "▁▂▃▄▅▆▇█"
+sparkline([3,3,3]) is "▁▁▁"
+
+
+
### stddev
stddev (class=stats #args=1) Returns the sample standard deviation of values in an array or map. Returns empty string AKA void for array/map of length less than two; returns error for non-array/non-map types.
diff --git a/docs/src/reference-verbs.md b/docs/src/reference-verbs.md
index 4a9eeb42b..a2fa85aee 100644
--- a/docs/src/reference-verbs.md
+++ b/docs/src/reference-verbs.md
@@ -54,7 +54,7 @@ These fall into categories as follows:
* `awk`-like functionality: [filter](reference-verbs.md#filter), [put](reference-verbs.md#put), [sec2gmt](reference-verbs.md#sec2gmt), [sec2gmtdate](reference-verbs.md#sec2gmtdate), [step](reference-verbs.md#step), [tee](reference-verbs.md#tee).
-* Statistically oriented: [bar](reference-verbs.md#bar), [bootstrap](reference-verbs.md#bootstrap), [decimate](reference-verbs.md#decimate), [histogram](reference-verbs.md#histogram), [least-frequent](reference-verbs.md#least-frequent), [most-frequent](reference-verbs.md#most-frequent), [sample](reference-verbs.md#sample), [shuffle](reference-verbs.md#shuffle), [stats1](reference-verbs.md#stats1), [stats2](reference-verbs.md#stats2).
+* Statistically oriented: [bar](reference-verbs.md#bar), [bootstrap](reference-verbs.md#bootstrap), [decimate](reference-verbs.md#decimate), [histogram](reference-verbs.md#histogram), [least-frequent](reference-verbs.md#least-frequent), [most-frequent](reference-verbs.md#most-frequent), [sample](reference-verbs.md#sample), [shuffle](reference-verbs.md#shuffle), [sparkline](reference-verbs.md#sparkline), [stats1](reference-verbs.md#stats1), [stats2](reference-verbs.md#stats2).
* Particularly oriented toward [Record Heterogeneity](record-heterogeneity.md), although all Miller commands can handle heterogeneous records: [group-by](reference-verbs.md#group-by), [group-like](reference-verbs.md#group-like), [having-fields](reference-verbs.md#having-fields).
@@ -1787,7 +1787,11 @@ Options:
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+-s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+With -s, output is one record per value-field, with a sparkline field
+instead of one record per bin.
This is just a histogram; there's not too much to say here. A note about binning, by example: Suppose you use `--lo 0.0 --hi 1.0 --nbins 10 -f x`. The input numbers less than 0 or greater than 1 aren't counted in any bin. Input numbers equal to 1 are counted in the last bin. That is, bin 0 has `0.0 < x < 0.1`, bin 1 has `0.1 < x < 0.2`, etc., but bin 9 has `0.9 < x < 1.0`.
@@ -1830,6 +1834,20 @@ my_bin_lo my_bin_hi my_x_count my_x2_count my_x3_count
0.9 1 1013 507 341
+Use `-s` for a compact one-line Unicode sparkline per field, rather than one output record per bin. Note this sparklines the *binned counts* -- i.e. the shape of the value distribution -- not the field's raw values in record order; for the latter, use [sparkline](reference-verbs.md#sparkline) instead:
+
+
+mlr --opprint put '$x2=$x**2;$x3=$x2*$x' \
+ then histogram -f x,x2,x3 --lo 0 --hi 1 --nbins 10 -s \
+ data/medium
+
+
+field lo hi sparkline
+x 0 1 █▁▆▄▂▄▅▅▄▅
+x2 0 1 █▃▂▂▂▁▁▁▁▁
+x3 0 1 █▂▂▂▁▁▁▁▁▁
+
+
## join
@@ -3392,6 +3410,38 @@ a b c
9 8 7
+## sparkline
+
+
+mlr sparkline --help
+
+
+Usage: mlr sparkline [options]
+Reduces numeric field(s), across all records in input order, to a compact
+Unicode sparkline -- one block character per record -- for visualizing
+trends. Emits one output record per field. Holds all records in memory
+before producing any output.
+Options:
+-f {a,b,c} Field names to sparkline.
+-h|--help Show this message.
+
+
+This reduces one or more numeric fields, in input-record order, to a compact
+Unicode sparkline -- a quick way to eyeball a trend across records without
+plotting software. Contrast with [histogram](reference-verbs.md#histogram)
+`-s`, which sparklines the *distribution* of a field's values (binned by
+value, order-independent) rather than the field's values in record order.
+
+
+mlr --icsv --opprint sparkline -f index,quantity,rate example.csv
+
+
+field n lo hi sparkline
+index 10 11 91 ▁▁▁▄▅▆▆▆██
+quantity 10 13.8103 81.229 ▄█▁████▆▆▇
+rate 10 0.013 9.887 █▁▃▆▇█▅▄▇▇
+
+
## sparsify
diff --git a/docs/src/reference-verbs.md.in b/docs/src/reference-verbs.md.in
index d469ffb80..ae897cf51 100644
--- a/docs/src/reference-verbs.md.in
+++ b/docs/src/reference-verbs.md.in
@@ -27,7 +27,7 @@ These fall into categories as follows:
* `awk`-like functionality: [filter](reference-verbs.md#filter), [put](reference-verbs.md#put), [sec2gmt](reference-verbs.md#sec2gmt), [sec2gmtdate](reference-verbs.md#sec2gmtdate), [step](reference-verbs.md#step), [tee](reference-verbs.md#tee).
-* Statistically oriented: [bar](reference-verbs.md#bar), [bootstrap](reference-verbs.md#bootstrap), [decimate](reference-verbs.md#decimate), [histogram](reference-verbs.md#histogram), [least-frequent](reference-verbs.md#least-frequent), [most-frequent](reference-verbs.md#most-frequent), [sample](reference-verbs.md#sample), [shuffle](reference-verbs.md#shuffle), [stats1](reference-verbs.md#stats1), [stats2](reference-verbs.md#stats2).
+* Statistically oriented: [bar](reference-verbs.md#bar), [bootstrap](reference-verbs.md#bootstrap), [decimate](reference-verbs.md#decimate), [histogram](reference-verbs.md#histogram), [least-frequent](reference-verbs.md#least-frequent), [most-frequent](reference-verbs.md#most-frequent), [sample](reference-verbs.md#sample), [shuffle](reference-verbs.md#shuffle), [sparkline](reference-verbs.md#sparkline), [stats1](reference-verbs.md#stats1), [stats2](reference-verbs.md#stats2).
* Particularly oriented toward [Record Heterogeneity](record-heterogeneity.md), although all Miller commands can handle heterogeneous records: [group-by](reference-verbs.md#group-by), [group-like](reference-verbs.md#group-like), [having-fields](reference-verbs.md#having-fields).
@@ -579,6 +579,14 @@ mlr --opprint put '$x2=$x**2;$x3=$x2*$x' \
data/medium
GENMD-EOF
+Use `-s` for a compact one-line Unicode sparkline per field, rather than one output record per bin. Note this sparklines the *binned counts* -- i.e. the shape of the value distribution -- not the field's raw values in record order; for the latter, use [sparkline](reference-verbs.md#sparkline) instead:
+
+GENMD-RUN-COMMAND
+mlr --opprint put '$x2=$x**2;$x3=$x2*$x' \
+ then histogram -f x,x2,x3 --lo 0 --hi 1 --nbins 10 -s \
+ data/medium
+GENMD-EOF
+
## join
GENMD-RUN-COMMAND
@@ -1017,6 +1025,22 @@ GENMD-RUN-COMMAND
mlr --ijson --opprint sort-within-records data/sort-within-records.json
GENMD-EOF
+## sparkline
+
+GENMD-RUN-COMMAND
+mlr sparkline --help
+GENMD-EOF
+
+This reduces one or more numeric fields, in input-record order, to a compact
+Unicode sparkline -- a quick way to eyeball a trend across records without
+plotting software. Contrast with [histogram](reference-verbs.md#histogram)
+`-s`, which sparklines the *distribution* of a field's values (binned by
+value, order-independent) rather than the field's values in record order.
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint sparkline -f index,quantity,rate example.csv
+GENMD-EOF
+
## sparsify
GENMD-RUN-COMMAND
diff --git a/man/manpage.txt b/man/manpage.txt
index b0d6322ca..56e848bb8 100644
--- a/man/manpage.txt
+++ b/man/manpage.txt
@@ -209,8 +209,8 @@
histogram json-parse json-stringify join label latin1-to-utf8 least-frequent
merge-fields most-frequent nest nothing put regularize remove-empty-columns
rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
- skip-trivial-records sort sort-within-records sparsify split ssub stats1
- stats2 step sub summary surv tac tail tee template top utf8-to-latin1
+ skip-trivial-records sort sort-within-records sparkline sparsify split ssub
+ stats1 stats2 step sub summary surv tac tail tee template top utf8-to-latin1
unflatten uniq unspace unsparsify
1mFUNCTION LIST0m
@@ -236,14 +236,14 @@
null_count os percentile percentiles pow qnorm reduce regextract
regextract_or_else rightpad round roundm rstrip sec2dhms sec2gmt sec2gmtdate
sec2hms sec2localdate sec2localtime select sgn sha1 sha256 sha512 sin sinh
- skewness sort sort_collection splita splitax splitkv splitkvx splitnv splitnvx
- sqrt ssub stat stddev strfntime strfntime_local strftime strftime_local string
- strip strlen strmatch strmatchx strpntime strpntime_local strptime
- strptime_local sub substr substr0 substr1 sum sum2 sum3 sum4 sysntime system
- systime systimeint tan tanh tolower toupper truncate typeof unflatten unformat
- unformatx upntime uptime urand urand32 urandelement urandint urandrange
- utf8_to_latin1 variance version ! != !=~ % & && * ** + - . .* .+ .- ./ / // <
- << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
+ skewness sort sort_collection sparkline splita splitax splitkv splitkvx
+ splitnv splitnvx sqrt ssub stat stddev strfntime strfntime_local strftime
+ strftime_local string strip strlen strmatch strmatchx strpntime
+ strpntime_local strptime strptime_local sub substr substr0 substr1 sum sum2
+ sum3 sum4 sysntime system systime systimeint tan tanh tolower toupper truncate
+ typeof unflatten unformat unformatx upntime uptime urand urand32 urandelement
+ urandint urandrange utf8_to_latin1 variance version ! != !=~ % & && * ** + - .
+ .* .+ .- ./ / // < << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
1mCOMMENTS-IN-DATA FLAGS0m
Miller lets you put comments in your data, such as
@@ -1441,7 +1441,11 @@
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+ -s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+ With -s, output is one record per value-field, with a sparkline field
+ instead of one record per bin.
1mjson-parse0m
Usage: mlr json-parse [options]
@@ -2062,6 +2066,16 @@
-n Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
-h|--help Show this message.
+ 1msparkline0m
+ Usage: mlr sparkline [options]
+ Reduces numeric field(s), across all records in input order, to a compact
+ Unicode sparkline -- one block character per record -- for visualizing
+ trends. Emits one output record per field. Holds all records in memory
+ before producing any output.
+ Options:
+ -f {a,b,c} Field names to sparkline.
+ -h|--help Show this message.
+
1msparsify0m
Usage: mlr sparsify [options]
Unsets fields for which the key is the empty string (or, optionally, another
@@ -3263,6 +3277,12 @@
1msort_collection0m
(class=stats #args=1) This is a helper function for the percentiles function; please see its online help for details.
+ 1msparkline0m
+ (class=stats #args=1) Returns a string of Unicode block characters (one of per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.
+ Examples:
+ sparkline([1,2,3,4,5,6,7,8]) is ""
+ sparkline([3,3,3]) is ""
+
1msplita0m
(class=conversion #args=2) Splits string into array with type inference. First argument is string to split; second is the separator to split on.
Example:
@@ -4041,4 +4061,4 @@
MIME Type for Comma-Separated Values (CSV) Files, the Miller docsite
https://miller.readthedocs.io
- 2026-07-06 4mMILLER24m(1)
+ 2026-07-07 4mMILLER24m(1)
diff --git a/man/mlr.1 b/man/mlr.1
index 1578a7e64..1d955610a 100644
--- a/man/mlr.1
+++ b/man/mlr.1
@@ -2,12 +2,12 @@
.\" Title: mlr
.\" Author: [see the "AUTHOR" section]
.\" Generator: ./mkman.rb
-.\" Date: 2026-07-06
+.\" Date: 2026-07-07
.\" Manual: \ \&
.\" Source: \ \&
.\" Language: English
.\"
-.TH "MILLER" "1" "2026-07-06" "\ \&" "\ \&"
+.TH "MILLER" "1" "2026-07-07" "\ \&" "\ \&"
.\" -----------------------------------------------------------------
.\" * Portability definitions
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -251,8 +251,8 @@ format-values fraction gap grep group-by group-like gsub having-fields head
histogram json-parse json-stringify join label latin1-to-utf8 least-frequent
merge-fields most-frequent nest nothing put regularize remove-empty-columns
rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
-skip-trivial-records sort sort-within-records sparsify split ssub stats1
-stats2 step sub summary surv tac tail tee template top utf8-to-latin1
+skip-trivial-records sort sort-within-records sparkline sparsify split ssub
+stats1 stats2 step sub summary surv tac tail tee template top utf8-to-latin1
unflatten uniq unspace unsparsify
.fi
.if n \{\
@@ -284,14 +284,14 @@ minlen mmul mode msub next nsec2gmt nsec2gmtdate nsec2localdate nsec2localtime
null_count os percentile percentiles pow qnorm reduce regextract
regextract_or_else rightpad round roundm rstrip sec2dhms sec2gmt sec2gmtdate
sec2hms sec2localdate sec2localtime select sgn sha1 sha256 sha512 sin sinh
-skewness sort sort_collection splita splitax splitkv splitkvx splitnv splitnvx
-sqrt ssub stat stddev strfntime strfntime_local strftime strftime_local string
-strip strlen strmatch strmatchx strpntime strpntime_local strptime
-strptime_local sub substr substr0 substr1 sum sum2 sum3 sum4 sysntime system
-systime systimeint tan tanh tolower toupper truncate typeof unflatten unformat
-unformatx upntime uptime urand urand32 urandelement urandint urandrange
-utf8_to_latin1 variance version ! != !=~ % & && * ** + - . .* .+ .- ./ / // <
-<< <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
+skewness sort sort_collection sparkline splita splitax splitkv splitkvx
+splitnv splitnvx sqrt ssub stat stddev strfntime strfntime_local strftime
+strftime_local string strip strlen strmatch strmatchx strpntime
+strpntime_local strptime strptime_local sub substr substr0 substr1 sum sum2
+sum3 sum4 sysntime system systime systimeint tan tanh tolower toupper truncate
+typeof unflatten unformat unformatx upntime uptime urand urand32 urandelement
+urandint urandrange utf8_to_latin1 variance version ! != !=~ % & && * ** + - .
+\&.* .+ .- ./ / // < << <= <=> == =~ > >= >> >>> ?: ?? ??? ^ ^^ | || ~
.fi
.if n \{\
.RE
@@ -1791,7 +1791,11 @@ Options:
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+-s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+With -s, output is one record per value-field, with a sparkline field
+instead of one record per bin.
.fi
.if n \{\
.RE
@@ -2564,6 +2568,22 @@ Options:
.fi
.if n \{\
.RE
+.SS "sparkline"
+.if n \{\
+.RS 0
+.\}
+.nf
+Usage: mlr sparkline [options]
+Reduces numeric field(s), across all records in input order, to a compact
+Unicode sparkline -- one block character per record -- for visualizing
+trends. Emits one output record per field. Holds all records in memory
+before producing any output.
+Options:
+-f {a,b,c} Field names to sparkline.
+-h|--help Show this message.
+.fi
+.if n \{\
+.RE
.SS "sparsify"
.if n \{\
.RS 0
@@ -4931,6 +4951,18 @@ Map without function: sort({"c":2,"a":3,"b":1}, "vnr") returns {"a":3,"c":2,"b":
.fi
.if n \{\
.RE
+.SS "sparkline"
+.if n \{\
+.RS 0
+.\}
+.nf
+ (class=stats #args=1) Returns a string of Unicode block characters (one of ▁▂▃▄▅▆▇█ per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.
+Examples:
+sparkline([1,2,3,4,5,6,7,8]) is "▁▂▃▄▅▆▇█"
+sparkline([3,3,3]) is "▁▁▁"
+.fi
+.if n \{\
+.RE
.SS "splita"
.if n \{\
.RS 0
diff --git a/pkg/bifs/sparkline.go b/pkg/bifs/sparkline.go
new file mode 100644
index 000000000..e791200b7
--- /dev/null
+++ b/pkg/bifs/sparkline.go
@@ -0,0 +1,72 @@
+package bifs
+
+import (
+ "github.com/johnkerl/miller/v6/pkg/mlrval"
+)
+
+// sparklineTicks are the eighth-height Unicode block characters used to
+// render array/map values as a compact one-line bar chart.
+var sparklineTicks = []rune("▁▂▃▄▅▆▇█")
+
+func BIF_sparkline(collection *mlrval.Mlrval) *mlrval.Mlrval {
+ ok, valueIfNot := check_collection(collection, "sparkline")
+ if !ok {
+ return valueIfNot
+ }
+
+ var floatValues []float64
+ if collection.IsArray() {
+ array := collection.AcquireArrayValue()
+ floatValues = make([]float64, 0, len(array))
+ for _, element := range array {
+ floatValue, isFloat := element.GetNumericToFloatValue()
+ if !isFloat {
+ return mlrval.FromNotNumericError("sparkline", element)
+ }
+ floatValues = append(floatValues, floatValue)
+ }
+ } else {
+ m := collection.AcquireMapValue()
+ floatValues = make([]float64, 0, m.FieldCount)
+ for pe := m.Head; pe != nil; pe = pe.Next {
+ floatValue, isFloat := pe.Value.GetNumericToFloatValue()
+ if !isFloat {
+ return mlrval.FromNotNumericError("sparkline", pe.Value)
+ }
+ floatValues = append(floatValues, floatValue)
+ }
+ }
+
+ if len(floatValues) == 0 {
+ return mlrval.VOID
+ }
+
+ lo := floatValues[0]
+ hi := floatValues[0]
+ for _, floatValue := range floatValues[1:] {
+ if floatValue < lo {
+ lo = floatValue
+ }
+ if floatValue > hi {
+ hi = floatValue
+ }
+ }
+
+ numTicks := len(sparklineTicks)
+ runes := make([]rune, len(floatValues))
+ for i, floatValue := range floatValues {
+ if hi == lo {
+ runes[i] = sparklineTicks[0]
+ continue
+ }
+ tickIndex := int(float64(numTicks-1)*(floatValue-lo)/(hi-lo) + 0.5)
+ if tickIndex < 0 {
+ tickIndex = 0
+ } else if tickIndex >= numTicks {
+ tickIndex = numTicks - 1
+ }
+ runes[i] = sparklineTicks[tickIndex]
+ }
+
+ return mlrval.FromString(string(runes))
+}
diff --git a/pkg/bifs/sparkline_test.go b/pkg/bifs/sparkline_test.go
new file mode 100644
index 000000000..858ab8c16
--- /dev/null
+++ b/pkg/bifs/sparkline_test.go
@@ -0,0 +1,60 @@
+package bifs
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+
+ "github.com/johnkerl/miller/v6/pkg/mlrval"
+)
+
+func TestBIF_sparkline(t *testing.T) {
+ // Needs array or map
+ input := mlrval.FromInt(3)
+ output := BIF_sparkline(input)
+ assert.True(t, output.IsError())
+
+ // Non-numeric element
+ input = mlrval.FromArray([]*mlrval.Mlrval{
+ mlrval.FromInt(1),
+ mlrval.FromString("abc"),
+ })
+ output = BIF_sparkline(input)
+ assert.True(t, output.IsError())
+
+ // Empty array is void
+ input = mlrval.FromArray([]*mlrval.Mlrval{})
+ output = BIF_sparkline(input)
+ assert.True(t, output.IsVoid())
+
+ // Ascending values span the full tick range, low to high
+ input = mlrval.FromArray([]*mlrval.Mlrval{
+ mlrval.FromInt(1),
+ mlrval.FromInt(2),
+ mlrval.FromInt(3),
+ mlrval.FromInt(4),
+ mlrval.FromInt(5),
+ mlrval.FromInt(6),
+ mlrval.FromInt(7),
+ mlrval.FromInt(8),
+ })
+ output = BIF_sparkline(input)
+ assert.True(t, mlrval.Equals(output, mlrval.FromString("▁▂▃▄▅▆▇█")))
+
+ // Same value throughout maps to the lowest tick
+ input = mlrval.FromArray([]*mlrval.Mlrval{
+ mlrval.FromInt(3),
+ mlrval.FromInt(3),
+ mlrval.FromInt(3),
+ })
+ output = BIF_sparkline(input)
+ assert.True(t, mlrval.Equals(output, mlrval.FromString("▁▁▁")))
+
+ // Map input follows insertion order
+ input = array_to_map_for_test(mlrval.FromArray([]*mlrval.Mlrval{
+ mlrval.FromInt(1),
+ mlrval.FromInt(8),
+ }))
+ output = BIF_sparkline(input)
+ assert.True(t, mlrval.Equals(output, mlrval.FromString("▁█")))
+}
diff --git a/pkg/dsl/cst/builtin_function_manager.go b/pkg/dsl/cst/builtin_function_manager.go
index 953717308..b5130afbd 100644
--- a/pkg/dsl/cst/builtin_function_manager.go
+++ b/pkg/dsl/cst/builtin_function_manager.go
@@ -1097,6 +1097,17 @@ is normally distributed.`,
},
},
+ {
+ name: "sparkline",
+ class: FUNC_CLASS_STATS,
+ help: `Returns a string of Unicode block characters (one of ▁▂▃▄▅▆▇█ per element) representing the relative magnitudes of values in an array or map, for a compact ASCII/Unicode bar chart. Returns error for non-array/non-map types.`,
+ unaryFunc: bifs.BIF_sparkline,
+ examples: []string{
+ `sparkline([1,2,3,4,5,6,7,8]) is "▁▂▃▄▅▆▇█"`,
+ `sparkline([3,3,3]) is "▁▁▁"`,
+ },
+ },
+
{
name: "mode",
class: FUNC_CLASS_STATS,
diff --git a/pkg/transformers/aaa_transformer_table.go b/pkg/transformers/aaa_transformer_table.go
index a0f4aab5d..bb49e0098 100644
--- a/pkg/transformers/aaa_transformer_table.go
+++ b/pkg/transformers/aaa_transformer_table.go
@@ -62,6 +62,7 @@ var TRANSFORMER_LOOKUP_TABLE = []TransformerSetup{
SkipTrivialRecordsSetup,
SortSetup,
SortWithinRecordsSetup,
+ SparklineSetup,
SparsifySetup,
SplitSetup,
SsubSetup,
diff --git a/pkg/transformers/histogram.go b/pkg/transformers/histogram.go
index 53ccdc859..2c71e5474 100644
--- a/pkg/transformers/histogram.go
+++ b/pkg/transformers/histogram.go
@@ -5,6 +5,7 @@ import (
"os"
"strings"
+ "github.com/johnkerl/miller/v6/pkg/bifs"
"github.com/johnkerl/miller/v6/pkg/cli"
"github.com/johnkerl/miller/v6/pkg/lib"
"github.com/johnkerl/miller/v6/pkg/mlrval"
@@ -21,6 +22,7 @@ var histogramOptions = []OptionSpec{
{Flag: "--nbins", Arg: "{n}", Type: "int", Desc: "Number of histogram bins. Defaults to 20."},
{Flag: "--auto", Type: "bool", Desc: "Automatically computes limits, ignoring --lo and --hi. Holds all values in memory before producing any output."},
{Flag: "-o", Arg: "{prefix}", Type: "string", Desc: "Prefix for output field name. Default: no prefix."},
+ {Flag: "-s", Type: "bool", Desc: "Print a one-line Unicode sparkline per field instead of per-bin counts."},
}
var HistogramSetup = TransformerSetup{
@@ -39,6 +41,8 @@ func transformerHistogramUsage(
fmt.Fprintf(o, "Just a histogram. Input values < lo or > hi are not counted.\n")
fmt.Fprintf(o, "Usage: %s %s [options]\n", argv0, verb)
WriteVerbOptions(o, histogramOptions)
+ fmt.Fprintf(o, "With -s, output is one record per value-field, with a sparkline field\n")
+ fmt.Fprintf(o, "instead of one record per bin.\n")
}
func transformerHistogramParseCLI(
@@ -61,6 +65,7 @@ func transformerHistogramParseCLI(
hi := 0.0
doAuto := false
outputPrefix := ""
+ doSparkline := false
var err error
for argi < argc /* variable increment: 1 or 2 depending on flag */ {
@@ -111,6 +116,9 @@ func transformerHistogramParseCLI(
return nil, err
}
+ case "-s":
+ doSparkline = true
+
default:
return nil, cli.VerbErrorf(verb, "option \"%s\" not recognized", opt)
}
@@ -140,6 +148,7 @@ func transformerHistogramParseCLI(
hi,
doAuto,
outputPrefix,
+ doSparkline,
)
if err != nil {
return nil, err
@@ -160,6 +169,7 @@ type TransformerHistogram struct {
countsByField map[string][]int64
vectorsByFieldName map[string][]float64 // For auto-mode
outputPrefix string
+ doSparkline bool
recordTransformerFunc RecordTransformerFunc
}
@@ -171,6 +181,7 @@ func NewTransformerHistogram(
hi float64,
doAuto bool,
outputPrefix string,
+ doSparkline bool,
) (*TransformerHistogram, error) {
countsByField := make(map[string][]int64)
@@ -185,6 +196,7 @@ func NewTransformerHistogram(
valueFieldNames: valueFieldNames,
countsByField: countsByField,
outputPrefix: outputPrefix,
+ doSparkline: doSparkline,
nbins: nbins,
}
@@ -256,10 +268,40 @@ func (tr *TransformerHistogram) ingestNonAuto(
}
}
+// sparklineRecord summarizes a field's binned counts as a single record with
+// a Unicode-block sparkline field, rather than one record per bin.
+func (tr *TransformerHistogram) sparklineRecord(
+ valueFieldName string,
+ lo float64,
+ hi float64,
+) *mlrval.Mlrmap {
+ counts := tr.countsByField[valueFieldName]
+ countMlrvals := make([]*mlrval.Mlrval, len(counts))
+ for i, count := range counts {
+ countMlrvals[i] = mlrval.FromInt(count)
+ }
+ sparkline := bifs.BIF_sparkline(mlrval.FromArray(countMlrvals))
+
+ outrec := mlrval.NewMlrmapAsRecord()
+ outrec.PutReference(tr.outputPrefix+"field", mlrval.FromString(valueFieldName))
+ outrec.PutReference(tr.outputPrefix+"lo", mlrval.FromFloat(lo))
+ outrec.PutReference(tr.outputPrefix+"hi", mlrval.FromFloat(hi))
+ outrec.PutReference(tr.outputPrefix+"sparkline", sparkline)
+ return outrec
+}
+
func (tr *TransformerHistogram) emitNonAuto(
endOfStreamContext *types.Context,
outputRecordsAndContexts *[]*types.RecordAndContext, // list of *types.RecordAndContext
) {
+ if tr.doSparkline {
+ for _, valueFieldName := range tr.valueFieldNames {
+ outrec := tr.sparklineRecord(valueFieldName, tr.lo, tr.hi)
+ *outputRecordsAndContexts = append(*outputRecordsAndContexts, types.NewRecordAndContext(outrec, endOfStreamContext))
+ }
+ return
+ }
+
countFieldNames := make(map[string]string)
for _, valueFieldName := range tr.valueFieldNames {
countFieldNames[valueFieldName] = tr.outputPrefix + valueFieldName + "_count"
@@ -363,6 +405,14 @@ func (tr *TransformerHistogram) emitAuto(
}
}
+ if tr.doSparkline {
+ for _, valueFieldName := range tr.valueFieldNames {
+ outrec := tr.sparklineRecord(valueFieldName, lo, hi)
+ *outputRecordsAndContexts = append(*outputRecordsAndContexts, types.NewRecordAndContext(outrec, endOfStreamContext))
+ }
+ return
+ }
+
// Emission pass
countFieldNames := make(map[string]string)
for _, valueFieldName := range tr.valueFieldNames {
diff --git a/pkg/transformers/sparkline.go b/pkg/transformers/sparkline.go
new file mode 100644
index 000000000..5bf0bf802
--- /dev/null
+++ b/pkg/transformers/sparkline.go
@@ -0,0 +1,182 @@
+package transformers
+
+import (
+ "fmt"
+ "os"
+ "strings"
+
+ "github.com/johnkerl/miller/v6/pkg/bifs"
+ "github.com/johnkerl/miller/v6/pkg/cli"
+ "github.com/johnkerl/miller/v6/pkg/mlrval"
+ "github.com/johnkerl/miller/v6/pkg/types"
+)
+
+const verbNameSparkline = "sparkline"
+
+var sparklineOptions = []OptionSpec{
+ {Flag: "-f", Arg: "{a,b,c}", Type: "csv-list", Desc: "Field names to sparkline."},
+}
+
+var SparklineSetup = TransformerSetup{
+ Verb: verbNameSparkline,
+ UsageFunc: transformerSparklineUsage,
+ ParseCLIFunc: transformerSparklineParseCLI,
+ IgnoresInput: false,
+ Options: sparklineOptions,
+}
+
+func transformerSparklineUsage(
+ o *os.File,
+) {
+ fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameSparkline)
+ fmt.Fprintf(o, "Reduces numeric field(s), across all records in input order, to a compact\n")
+ fmt.Fprintf(o, "Unicode sparkline -- one block character per record -- for visualizing\n")
+ fmt.Fprintf(o, "trends. Emits one output record per field. Holds all records in memory\n")
+ fmt.Fprintf(o, "before producing any output.\n")
+ WriteVerbOptions(o, sparklineOptions)
+}
+
+func transformerSparklineParseCLI(
+ pargi *int,
+ argc int,
+ args []string,
+ _ *cli.TOptions,
+ doConstruct bool, // false for first pass of CLI-parse, true for second pass
+) (RecordTransformer, error) {
+
+ // Skip the verb name from the current spot in the mlr command line
+ argi := *pargi
+ verb := args[argi]
+ argi++
+
+ // Parse local flags
+ var err error
+ var fieldNames []string = nil
+
+ for argi < argc /* variable increment: 1 or 2 depending on flag */ {
+ opt := args[argi]
+ if !strings.HasPrefix(opt, "-") {
+ break // No more flag options to process
+ }
+ if args[argi] == "--" {
+ break // All transformers must do this so main-flags can follow verb-flags
+ }
+ argi++
+
+ switch opt {
+ case "-h", "--help":
+ transformerSparklineUsage(os.Stdout)
+ return nil, cli.ErrHelpRequested
+
+ case "-f":
+ fieldNames, err = cli.VerbGetStringArrayArg(verb, opt, args, &argi, argc)
+ if err != nil {
+ return nil, err
+ }
+
+ default:
+ return nil, cli.VerbErrorf(verb, "option \"%s\" not recognized", opt)
+ }
+ }
+
+ if fieldNames == nil {
+ return nil, cli.VerbErrorf(verb, "-f field names required")
+ }
+
+ *pargi = argi
+ if !doConstruct { // All transformers must do this for main command-line parsing
+ return nil, nil
+ }
+
+ transformer, err := NewTransformerSparkline(fieldNames)
+ if err != nil {
+ return nil, err
+ }
+
+ return transformer, nil
+}
+
+type TransformerSparkline struct {
+ fieldNames []string
+ valuesByField map[string][]*mlrval.Mlrval
+}
+
+func NewTransformerSparkline(
+ fieldNames []string,
+) (*TransformerSparkline, error) {
+ valuesByField := make(map[string][]*mlrval.Mlrval)
+ for _, fieldName := range fieldNames {
+ valuesByField[fieldName] = make([]*mlrval.Mlrval, 0)
+ }
+ return &TransformerSparkline{
+ fieldNames: fieldNames,
+ valuesByField: valuesByField,
+ }, nil
+}
+
+func (tr *TransformerSparkline) Transform(
+ inrecAndContext *types.RecordAndContext,
+ outputRecordsAndContexts *[]*types.RecordAndContext, // list of *types.RecordAndContext
+ inputDownstreamDoneChannel <-chan bool,
+ outputDownstreamDoneChannel chan<- bool,
+) {
+ HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
+
+ if !inrecAndContext.EndOfStream {
+ inrec := inrecAndContext.Record
+ for _, fieldName := range tr.fieldNames {
+ mvalue := inrec.Get(fieldName)
+ if mvalue != nil {
+ tr.valuesByField[fieldName] = append(tr.valuesByField[fieldName], mvalue.Copy())
+ }
+ }
+ return
+ }
+
+ // Else, end of stream: emit one summary record per field.
+ for _, fieldName := range tr.fieldNames {
+ values := tr.valuesByField[fieldName]
+
+ outrec := mlrval.NewMlrmapAsRecord()
+ outrec.PutReference("field", mlrval.FromString(fieldName))
+ outrec.PutReference("n", mlrval.FromInt(int64(len(values))))
+
+ sparkline := bifs.BIF_sparkline(mlrval.FromArray(values))
+ if !sparkline.IsError() {
+ lo, hi, haveLoHi := floatRangeOf(values)
+ if haveLoHi {
+ outrec.PutReference("lo", mlrval.FromFloat(lo))
+ outrec.PutReference("hi", mlrval.FromFloat(hi))
+ }
+ }
+ outrec.PutReference("sparkline", sparkline)
+
+ *outputRecordsAndContexts = append(*outputRecordsAndContexts, types.NewRecordAndContext(outrec, &inrecAndContext.Context))
+ }
+
+ *outputRecordsAndContexts = append(*outputRecordsAndContexts, inrecAndContext) // Emit the end-of-stream marker
+}
+
+// floatRangeOf returns the min and max of the numeric values, and whether
+// any were found.
+func floatRangeOf(values []*mlrval.Mlrval) (lo float64, hi float64, haveLoHi bool) {
+ for _, value := range values {
+ floatValue, isFloat := value.GetNumericToFloatValue()
+ if !isFloat {
+ continue
+ }
+ if !haveLoHi {
+ lo = floatValue
+ hi = floatValue
+ haveLoHi = true
+ } else {
+ if floatValue < lo {
+ lo = floatValue
+ }
+ if floatValue > hi {
+ hi = floatValue
+ }
+ }
+ }
+ return lo, hi, haveLoHi
+}
diff --git a/test/cases/cli-help/0001/expout b/test/cases/cli-help/0001/expout
index 51ccd63c4..9399b12b3 100644
--- a/test/cases/cli-help/0001/expout
+++ b/test/cases/cli-help/0001/expout
@@ -474,7 +474,11 @@ Options:
--auto Automatically computes limits, ignoring --lo and --hi. Holds all
values in memory before producing any output.
-o {prefix} Prefix for output field name. Default: no prefix.
+-s Print a one-line Unicode sparkline per field instead of per-bin
+ counts.
-h|--help Show this message.
+With -s, output is one record per value-field, with a sparkline field
+instead of one record per bin.
================================================================
json-parse
@@ -1120,6 +1124,17 @@ Options:
-n Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
-h|--help Show this message.
+================================================================
+sparkline
+Usage: mlr sparkline [options]
+Reduces numeric field(s), across all records in input order, to a compact
+Unicode sparkline -- one block character per record -- for visualizing
+trends. Emits one output record per field. Holds all records in memory
+before producing any output.
+Options:
+-f {a,b,c} Field names to sparkline.
+-h|--help Show this message.
+
================================================================
sparsify
Usage: mlr sparsify [options]
diff --git a/test/cases/dsl-stats/sparkline/various/cmd b/test/cases/dsl-stats/sparkline/various/cmd
new file mode 100644
index 000000000..8e64fdff2
--- /dev/null
+++ b/test/cases/dsl-stats/sparkline/various/cmd
@@ -0,0 +1 @@
+mlr -n --ofmtf 6 --xtab put -f ${CASEDIR}/mlr
diff --git a/test/cases/dsl-stats/sparkline/various/experr b/test/cases/dsl-stats/sparkline/various/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/dsl-stats/sparkline/various/expout b/test/cases/dsl-stats/sparkline/various/expout
new file mode 100644
index 000000000..32ab67b85
--- /dev/null
+++ b/test/cases/dsl-stats/sparkline/various/expout
@@ -0,0 +1,22 @@
+sparkline_0 (error)
+sparkline_0_type error
+sparkline_null (error)
+sparkline_null_type error
+sparkline_empty_array
+sparkline_empty_array_type empty
+sparkline_array_1 ▁
+sparkline_array_1_type string
+sparkline_array_flat ▁▁▁
+sparkline_array_flat_type string
+sparkline_array_ascending ▁▂▃▄▅▆▇█
+sparkline_array_ascending_type string
+sparkline_array_descending █▇▆▅▄▃▂▁
+sparkline_array_descending_type string
+sparkline_array_nonnumeric (error)
+sparkline_array_nonnumeric_type error
+sparkline_empty_map
+sparkline_empty_map_type empty
+sparkline_map_1 ▁
+sparkline_map_1_type string
+sparkline_map_ascending ▁▄█
+sparkline_map_ascending_type string
diff --git a/test/cases/dsl-stats/sparkline/various/mlr b/test/cases/dsl-stats/sparkline/various/mlr
new file mode 100644
index 000000000..c99e5796f
--- /dev/null
+++ b/test/cases/dsl-stats/sparkline/various/mlr
@@ -0,0 +1,27 @@
+end {
+ outputs = {};
+
+ outputs["sparkline_0"] = sparkline(0);
+ outputs["sparkline_null"] = sparkline(null);
+ outputs["sparkline_nonesuch"] = sparkline(nonesuch);
+
+ outputs["sparkline_empty_array"] = sparkline([]);
+ outputs["sparkline_array_1"] = sparkline([7]);
+ outputs["sparkline_array_flat"] = sparkline([3,3,3]);
+ outputs["sparkline_array_ascending"] = sparkline([1,2,3,4,5,6,7,8]);
+ outputs["sparkline_array_descending"] = sparkline([8,7,6,5,4,3,2,1]);
+ outputs["sparkline_array_nonnumeric"] = sparkline([1,"abc"]);
+
+ outputs["sparkline_empty_map"] = sparkline({});
+ outputs["sparkline_map_1"] = sparkline({ "a" : 7 });
+ outputs["sparkline_map_ascending"] = sparkline({ "a" : 1, "b" : 4, "c" : 8 });
+
+ typed_outputs = {};
+
+ for (k, v in outputs) {
+ typed_outputs[k] = v;
+ typed_outputs[k."_type"] = typeof(v);
+ }
+
+ emit typed_outputs;
+}
diff --git a/test/cases/verb-histogram/0008/cmd b/test/cases/verb-histogram/0008/cmd
new file mode 100644
index 000000000..7f38f998b
--- /dev/null
+++ b/test/cases/verb-histogram/0008/cmd
@@ -0,0 +1 @@
+mlr --icsv --opprint histogram --nbins 9 --auto -f x,y -s test/input/histo2.csv
diff --git a/test/cases/verb-histogram/0008/experr b/test/cases/verb-histogram/0008/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-histogram/0008/expout b/test/cases/verb-histogram/0008/expout
new file mode 100644
index 000000000..fb9591d33
--- /dev/null
+++ b/test/cases/verb-histogram/0008/expout
@@ -0,0 +1,3 @@
+field lo hi sparkline
+x 20.00000000 300.00000000 ▁▁▅▁▁█▁▁▅
+y 20.00000000 300.00000000 █▃▁▁▁▁▁▁▁
diff --git a/test/cases/verb-sparkline/0001/cmd b/test/cases/verb-sparkline/0001/cmd
new file mode 100644
index 000000000..a9f76465a
--- /dev/null
+++ b/test/cases/verb-sparkline/0001/cmd
@@ -0,0 +1 @@
+mlr --ojson sparkline -f i,x,y test/input/abixy
diff --git a/test/cases/verb-sparkline/0001/experr b/test/cases/verb-sparkline/0001/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sparkline/0001/expout b/test/cases/verb-sparkline/0001/expout
new file mode 100644
index 000000000..64dfa4158
--- /dev/null
+++ b/test/cases/verb-sparkline/0001/expout
@@ -0,0 +1,23 @@
+[
+{
+ "field": "i",
+ "n": 10,
+ "lo": 1.00000000,
+ "hi": 10.00000000,
+ "sparkline": "▁▂▃▃▄▅▆▆▇█"
+},
+{
+ "field": "x",
+ "n": 10,
+ "lo": 0.03144188,
+ "hi": 0.75867996,
+ "sparkline": "▄█▃▄▆▆▇▆▁▆"
+},
+{
+ "field": "y",
+ "n": 10,
+ "lo": 0.13418874,
+ "hi": 0.97618139,
+ "sparkline": "▆▄▃▁▇▄▁█▆█"
+}
+]
diff --git a/test/cases/verb-sparkline/0002/cmd b/test/cases/verb-sparkline/0002/cmd
new file mode 100644
index 000000000..8f0ce6a63
--- /dev/null
+++ b/test/cases/verb-sparkline/0002/cmd
@@ -0,0 +1 @@
+mlr --opprint sparkline -f i test/input/abixy
diff --git a/test/cases/verb-sparkline/0002/experr b/test/cases/verb-sparkline/0002/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sparkline/0002/expout b/test/cases/verb-sparkline/0002/expout
new file mode 100644
index 000000000..5b20af9bc
--- /dev/null
+++ b/test/cases/verb-sparkline/0002/expout
@@ -0,0 +1,2 @@
+field n lo hi sparkline
+i 10 1.00000000 10.00000000 ▁▂▃▃▄▅▆▆▇█
diff --git a/test/cases/verb-sparkline/0003/cmd b/test/cases/verb-sparkline/0003/cmd
new file mode 100644
index 000000000..cb9aaf4c2
--- /dev/null
+++ b/test/cases/verb-sparkline/0003/cmd
@@ -0,0 +1 @@
+mlr sparkline --help
diff --git a/test/cases/verb-sparkline/0003/experr b/test/cases/verb-sparkline/0003/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sparkline/0003/expout b/test/cases/verb-sparkline/0003/expout
new file mode 100644
index 000000000..07eea812c
--- /dev/null
+++ b/test/cases/verb-sparkline/0003/expout
@@ -0,0 +1,8 @@
+Usage: mlr sparkline [options]
+Reduces numeric field(s), across all records in input order, to a compact
+Unicode sparkline -- one block character per record -- for visualizing
+trends. Emits one output record per field. Holds all records in memory
+before producing any output.
+Options:
+-f {a,b,c} Field names to sparkline.
+-h|--help Show this message.
diff --git a/test/cases/verb-sparkline/0004/cmd b/test/cases/verb-sparkline/0004/cmd
new file mode 100644
index 000000000..cd795af18
--- /dev/null
+++ b/test/cases/verb-sparkline/0004/cmd
@@ -0,0 +1 @@
+mlr --ojson sparkline -f nonesuch,a test/input/abixy
diff --git a/test/cases/verb-sparkline/0004/experr b/test/cases/verb-sparkline/0004/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sparkline/0004/expout b/test/cases/verb-sparkline/0004/expout
new file mode 100644
index 000000000..4e6d4f65b
--- /dev/null
+++ b/test/cases/verb-sparkline/0004/expout
@@ -0,0 +1,12 @@
+[
+{
+ "field": "nonesuch",
+ "n": 0,
+ "sparkline": ""
+},
+{
+ "field": "a",
+ "n": 10,
+ "sparkline": (error)
+}
+]