1..
2    PLEASE DO NOT EDIT DIRECTLY. EDIT THE .rst.in FILE PLEASE.
3
4Quick examples
5================================================================
6
7Column select::
8
9    % mlr --csv cut -f hostname,uptime mydata.csv
10
11Add new columns as function of other columns::
12
13    % mlr --nidx put '$sum = $7 < 0.0 ? 3.5 : $7 + 2.1*$8' *.dat
14
15Row filter::
16
17    % mlr --csv filter '$status != "down" && $upsec >= 10000' *.csv
18
19Apply column labels and pretty-print::
20
21    % grep -v '^#' /etc/group | mlr --ifs : --nidx --opprint label group,pass,gid,member then sort -f group
22
23Join multiple data sources on key columns::
24
25    % mlr join -j account_id -f accounts.dat then group-by account_name balances.dat
26
27Multiple formats including JSON::
28
29    % mlr --json put '$attr = sub($attr, "([0-9]+)_([0-9]+)_.*", "\1:\2")' data/*.json
30
31Aggregate per-column statistics::
32
33    % mlr stats1 -a min,mean,max,p10,p50,p90 -f flag,u,v data/*
34
35Linear regression::
36
37    % mlr stats2 -a linreg-pca -f u,v -g shape data/*
38
39Aggregate custom per-column statistics::
40
41    % mlr put -q '@sum[$a][$b] += $x; end {emit @sum, "a", "b"}' data/*
42
43Iterate over data using DSL expressions::
44
45    % mlr --from estimates.tbl put '
46      for (k,v in $*) {
47        if (is_numeric(v) && k =~ "^[t-z].*$") {
48          $sum += v; $count += 1
49        }
50      }
51      $mean = $sum / $count # no assignment if count unset
52    '
53
54Run DSL expressions from a script file::
55
56    % mlr --from infile.dat put -f analyze.mlr
57
58Split/reduce output to multiple filenames::
59
60    % mlr --from infile.dat put 'tee > "./taps/data-".$a."-".$b, $*'
61
62Compressed I/O::
63
64    % mlr --from infile.dat put 'tee | "gzip > ./taps/data-".$a."-".$b.".gz", $*'
65
66Interoperate with other data-processing tools using standard pipes::
67
68    % mlr --from infile.dat put -q '@v=$*; dump | "jq .[]"'
69
70Tap/trace::
71
72    % mlr --from infile.dat put  '(NR % 1000 == 0) { print > stderr, "Checkpoint ".NR}'
73