17.5 CSV Files Filter

20210128 Select rows using the verb filter with both input and output as csv:

$ mlr --csv filter '$flag == 1' example.csv
color,shape,flag,index,quantity,rate
yellow,triangle,1,11,43.6498,9.8870
red,square,1,15,79.2778,0.0130
red,circle,1,16,13.8103,2.9010
yellow,circle,1,73,63.9785,4.2370
yellow,circle,1,87,63.5058,8.3350

Select rows using the verb filter on a character field:

$ mlr --csv filter '$color == "yellow"' example.csv
color,shape,flag,index,quantity,rate
yellow,triangle,1,11,43.6498,9.8870
yellow,circle,1,73,63.9785,4.2370
yellow,circle,1,87,63.5058,8.3350

Select rows using multiple filters (to limit the output):

$ mlr --csv filter '$color == "yellow"' then filter 'NR < 2' example.csv
color,shape,flag,index,quantity,rate
yellow,triangle,1,11,43.6498,9.8870

We can also ignore specific columns:

$ mlr --csv filter '$color == "yellow"' then put 'unset $index' example.csv
color,shape,flag,quantity,rate
yellow,triangle,1,43.6498,9.8870
yellow,circle,1,63.9785,4.2370
yellow,circle,1,63.5058,8.3350


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