mirror of
https://github.com/johnkerl/miller.git
synced 2026-08-03 21:13:09 +00:00
4f1424789e
* Docs6 proofreads batch 3 * BUild-everything script for local development * Start of glossary * Put quicklinks atop every page, not just the base-index page * Expanded record-heterogeneity page * streaming page * separators page * vimrc doc * separators page
234 lines
7.9 KiB
Markdown
234 lines
7.9 KiB
Markdown
<!--- PLEASE DO NOT EDIT DIRECTLY. EDIT THE .md.in FILE PLEASE. --->
|
|
<div>
|
|
<span class="quicklinks">
|
|
Quick links:
|
|
|
|
<a class="quicklink" href="../reference-verbs/index.html">Verb list</a>
|
|
|
|
<a class="quicklink" href="../reference-dsl-builtin-functions/index.html">Function list</a>
|
|
|
|
<a class="quicklink" href="../glossary/index.html">Glossary</a>
|
|
|
|
<a class="quicklink" href="https://github.com/johnkerl/miller" target="_blank">Repository ↗</a>
|
|
</span>
|
|
</div>
|
|
# DSL syntax
|
|
|
|
## Expression formatting
|
|
|
|
Multiple expressions may be given, separated by semicolons, and each may refer to the ones before:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>ruby -e '10.times{|i|puts "i=#{i}"}' | mlr --opprint put '$j = $i + 1; $k = $i +$j'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
i j k
|
|
0 1 1
|
|
1 2 3
|
|
2 3 5
|
|
3 4 7
|
|
4 5 9
|
|
5 6 11
|
|
6 7 13
|
|
7 8 15
|
|
8 9 17
|
|
9 10 19
|
|
</pre>
|
|
|
|
Newlines within the expression are ignored, which can help increase legibility of complex expressions:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --opprint put '</b>
|
|
<b> $nf = NF;</b>
|
|
<b> $nr = NR;</b>
|
|
<b> $fnr = FNR;</b>
|
|
<b> $filenum = FILENUM;</b>
|
|
<b> $filename = FILENAME</b>
|
|
<b>' data/small data/small2</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
a b i x y nf nr fnr filenum filename
|
|
pan pan 1 0.346791 0.726802 5 1 1 1 data/small
|
|
eks pan 2 0.758679 0.522151 5 2 2 1 data/small
|
|
wye wye 3 0.204603 0.338318 5 3 3 1 data/small
|
|
eks wye 4 0.381399 0.134188 5 4 4 1 data/small
|
|
wye pan 5 0.573288 0.863624 5 5 5 1 data/small
|
|
pan eks 9999 0.267481232652199086 0.557077185510228001 5 6 1 2 data/small2
|
|
wye eks 10000 0.734806020620654365 0.884788571337605134 5 7 2 2 data/small2
|
|
pan wye 10001 0.870530722602517626 0.009854780514656930 5 8 3 2 data/small2
|
|
hat wye 10002 0.321507044286237609 0.568893318795083758 5 9 4 2 data/small2
|
|
pan zee 10003 0.272054845593895200 0.425789896597056627 5 10 5 2 data/small2
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --opprint filter '($x > 0.5 && $y < 0.5) || ($x < 0.5 && $y > 0.5)' \</b>
|
|
<b> then stats2 -a corr -f x,y \</b>
|
|
<b> data/medium</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
x_y_corr
|
|
-0.7479940285189345
|
|
</pre>
|
|
|
|
## Expressions from files
|
|
|
|
The simplest way to enter expressions for `put` and `filter` is between single quotes on the command line (see also [here](miller-on-windows.md) for Windows). For example:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --from data/small put '$xy = sqrt($x**2 + $y**2)'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
a=pan,b=pan,i=1,x=0.346791,y=0.726802,xy=0.805298171415408
|
|
a=eks,b=pan,i=2,x=0.758679,y=0.522151,xy=0.9209970096813562
|
|
a=wye,b=wye,i=3,x=0.204603,y=0.338318,xy=0.3953750836016352
|
|
a=eks,b=wye,i=4,x=0.381399,y=0.134188,xy=0.40431623334340655
|
|
a=wye,b=pan,i=5,x=0.573288,y=0.863624,xy=1.036583592538489
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --from data/small put 'func f(a, b) { return sqrt(a**2 + b**2) } $xy = f($x, $y)'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
a=pan,b=pan,i=1,x=0.346791,y=0.726802,xy=0.805298171415408
|
|
a=eks,b=pan,i=2,x=0.758679,y=0.522151,xy=0.9209970096813562
|
|
a=wye,b=wye,i=3,x=0.204603,y=0.338318,xy=0.3953750836016352
|
|
a=eks,b=wye,i=4,x=0.381399,y=0.134188,xy=0.40431623334340655
|
|
a=wye,b=pan,i=5,x=0.573288,y=0.863624,xy=1.036583592538489
|
|
</pre>
|
|
|
|
You may, though, find it convenient to put expressions into files for reuse, and read them
|
|
**using the -f option**. For example:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>cat data/fe-example-3.mlr</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
func f(a, b) {
|
|
return sqrt(a**2 + b**2)
|
|
}
|
|
$xy = f($x, $y)
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --from data/small put -f data/fe-example-3.mlr</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
a=pan,b=pan,i=1,x=0.346791,y=0.726802,xy=0.805298171415408
|
|
a=eks,b=pan,i=2,x=0.758679,y=0.522151,xy=0.9209970096813562
|
|
a=wye,b=wye,i=3,x=0.204603,y=0.338318,xy=0.3953750836016352
|
|
a=eks,b=wye,i=4,x=0.381399,y=0.134188,xy=0.40431623334340655
|
|
a=wye,b=pan,i=5,x=0.573288,y=0.863624,xy=1.036583592538489
|
|
</pre>
|
|
|
|
If you have some of the logic in a file and you want to write the rest on the command line, you can **use the -f and -e options together**:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>cat data/fe-example-4.mlr</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
func f(a, b) {
|
|
return sqrt(a**2 + b**2)
|
|
}
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --from data/small put -f data/fe-example-4.mlr -e '$xy = f($x, $y)'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
a=pan,b=pan,i=1,x=0.346791,y=0.726802,xy=0.805298171415408
|
|
a=eks,b=pan,i=2,x=0.758679,y=0.522151,xy=0.9209970096813562
|
|
a=wye,b=wye,i=3,x=0.204603,y=0.338318,xy=0.3953750836016352
|
|
a=eks,b=wye,i=4,x=0.381399,y=0.134188,xy=0.40431623334340655
|
|
a=wye,b=pan,i=5,x=0.573288,y=0.863624,xy=1.036583592538489
|
|
</pre>
|
|
|
|
A suggested use-case here is defining functions in files, and calling them from command-line expressions.
|
|
|
|
Another suggested use-case is putting default parameter values in files, e.g. using `begin{@count=is_present(@count)?@count:10}` in the file, where you can precede that using `begin{@count=40}` using `-e`.
|
|
|
|
Moreover, you can have one or more `-f` expressions (maybe one function per file, for example) and one or more `-e` expressions on the command line. If you mix `-f` and `-e` then the expressions are evaluated in the order encountered.
|
|
|
|
## Semicolons, commas, newlines, and curly braces
|
|
|
|
Miller uses **semicolons as statement separators**, not statement terminators. This means you can write:
|
|
|
|
<pre class="pre-non-highlight-non-pair">
|
|
mlr put 'x=1'
|
|
mlr put 'x=1;$y=2'
|
|
mlr put 'x=1;$y=2;'
|
|
mlr put 'x=1;;;;$y=2;'
|
|
</pre>
|
|
|
|
Semicolons are optional after closing curly braces (which close conditionals and loops as discussed below).
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>echo x=1,y=2 | mlr put 'while (NF < 10) { $[NF+1] = ""} $foo = "bar"'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
x=1,y=2,3=,4=,5=,6=,7=,8=,9=,10=,foo=bar
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>echo x=1,y=2 | mlr put 'while (NF < 10) { $[NF+1] = ""}; $foo = "bar"'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
x=1,y=2,3=,4=,5=,6=,7=,8=,9=,10=,foo=bar
|
|
</pre>
|
|
|
|
Semicolons are required between statements even if those statements are on separate lines. **Newlines** are for your convenience but have no syntactic meaning: line endings do not terminate statements. For example, adjacent assignment statements must be separated by semicolons even if those statements are on separate lines:
|
|
|
|
<pre class="pre-non-highlight-non-pair">
|
|
mlr put '
|
|
$x = 1
|
|
$y = 2 # Syntax error
|
|
'
|
|
|
|
mlr put '
|
|
$x = 1;
|
|
$y = 2 # This is OK
|
|
'
|
|
</pre>
|
|
|
|
**Trailing commas** are allowed in function/subroutine definitions, function/subroutine callsites, and map literals. This is intended for (although not restricted to) the multi-line case:
|
|
|
|
<pre class="pre-highlight-in-pair">
|
|
<b>mlr --csvlite --from data/a.csv put '</b>
|
|
<b> func f(</b>
|
|
<b> num a,</b>
|
|
<b> num b,</b>
|
|
<b> ): num {</b>
|
|
<b> return a**2 + b**2;</b>
|
|
<b> }</b>
|
|
<b> $* = {</b>
|
|
<b> "s": $a + $b,</b>
|
|
<b> "t": $a - $b,</b>
|
|
<b> "u": f(</b>
|
|
<b> $a,</b>
|
|
<b> $b,</b>
|
|
<b> ),</b>
|
|
<b> "v": NR,</b>
|
|
<b> }</b>
|
|
<b>'</b>
|
|
</pre>
|
|
<pre class="pre-non-highlight-in-pair">
|
|
s,t,u,v
|
|
3,-1,5,1
|
|
9,-1,41,2
|
|
</pre>
|
|
|
|
Bodies for all compound statements must be enclosed in **curly braces**, even if the body is a single statement:
|
|
|
|
<pre class="pre-highlight-non-pair">
|
|
<b>mlr put 'if ($x == 1) $y = 2' # Syntax error</b>
|
|
</pre>
|
|
|
|
<pre class="pre-highlight-non-pair">
|
|
<b>mlr put 'if ($x == 1) { $y = 2 }' # This is OK</b>
|
|
</pre>
|
|
|
|
Bodies for compound statements may be empty:
|
|
|
|
<pre class="pre-highlight-non-pair">
|
|
<b>mlr put 'if ($x == 1) { }' # This no-op is syntactically acceptable</b>
|
|
</pre>
|
|
|