feature request: create new field from calculating length of string in field

[avilella]

Hi,

This is either a feature request or a question as to how to achieve in an elegant way:

Is there a way of creating a new field which is the length of the string in another field? E.g. in pseudocode below:

$ seq 1 10 | csvtk add-header -n field1 | csvtk mutate -f field1 -n f1_len -p '^length(.+)$'
field1,f1_len
1,1
2,1
3,1
4,1
5,1
6,1
7,1
8,1
9,1
10,2

Thanks in advance

[shenwei356]

sorry, not supported.

[tseemann]

@avilella i've been wanting this feature too.
I don't think datamash has it either.
Very frustrating to have to switch to awk or perl here.

[shenwei356]

@avilella @tseemann

$ (echo a; seq 0 42 200  ) \
    | csvtk mutate2 -t -n b -e "\$a + 50" -L 0 \
    | csvtk mutate2 -t -n len -e 'len($a, $b)'
a       b       len
0       50      3
42      92      4
84      134     5
126     176     6
168     218     6

• csvtk_darwin_amd64.tar.gz
• csvtk_linux_amd64.tar.gz
• csvtk_windows_amd64.exe.tar.gz

[avilella]

Fantastic! Thank you very much!

[tolot27]

@shenwei356 Please can you implement the len function in filter2 as well?

[shenwei356]

Sure, but it's midnight here, how about tomorrow.

And I decide to change expression evaluation package to https://github.com/antonmedv/expr someday , which has more functions. #172

[shenwei356]

Please can you implement the len function in filter2 as well?

Done. And also fixed len and ulen in mutate2, where it could not be used for arithmetic operators.

• csvtk_darwin_amd64.tar.gz
• csvtk_linux_amd64.tar.gz
• csvtk_windows_amd64.exe.tar.gz

[tolot27]

Many thanks @shenwei356. Unfortunately, this and the some other intermediate builds after 0.23 have a problem with mutate2. Windows and Linux version is affected. Most of the time, they report:

[ERRO] Invalid token: '_'
[ERRO] xopen: no content

But after running it ten or more times, it passes and returns a result. Shall I open a separate issue for that or report it a (non-working) example elsewhere?

[shenwei356]

Yes please open another issue with the demo file and commands.