joinp --infer-len=0 data type issue

[jqnatividad]

Discussed in #2402

^{Originally posted by datatraveller1 January 2, 2025}
With the qsv joinp --infer-len=0 command, some data types of the output file (-o joined.csv) seem to get changed.
E.g. there is a column (not part of the join columns) PT with original values 0101. The output column PT values get changed to 101. However, I don't want the output column content to be changed.
@jqnatividad If you need more information, I'll write an issue report tomorrow or latest this weekend. Thank you!

[jqnatividad]

Thanks for the report @datatraveller1.

Can you add some additional context and a minimal reproducible example?

v2.0.0 release is imminent, so it might be fixed by upstream changes in Polars.

I also fine-tuned the usage text to show the interplay between the --infer-len and --cache-schema options.

382c6e0

[datatraveller1]

Hi @jqnatividad,

ok, here is a little example:

file a.csv

art_no,PG,PT
1,104,0101
2,104,0101
3,104,0101

file b.csv

art_no,PG2,PT2
1,105,0101
3,105,0101
4,105,0101

command:
qsv joinp --infer-len=0 art_no a.csv art_no b.csv -o joined.csv

result joined.csv:

art_no,PG,PT,PG2,PT2
1,104,101,105,101
3,104,101,105,101

I want PT and PT2 to be depicted with the original values 0101 instead of 101

[datatraveller1]

BTW, without --infer-len=0 (qsv joinp art_no a.csv art_no b.csv -o joined.csv), the result is the same.