Please document expected behavior when default arguments are used.

[steve-the-bayesian]

This is a documentation request.

The docs for read_csv currently include the following:

index_col:
int, str, sequence of int / str, or False, default None
Column(s) to use as the row labels of the DataFrame, either given as string name or column index. If a sequence of int / str is given, a MultiIndex is used.

Note: index_col=False can be used to force pandas to not use the first column as the index, e.g. when you have a malformed file with delimiters at the end of each line.

Problem description

The docs explain how read_csv works in every case EXCEPT the default, which is the most common. Please document what happens when index_col=None is passed.

[TomAugspurger]

Can you submit a PR improving the documentation?

[steve-the-bayesian]

I'll give it a go. Full disclosure: I was looking at the docs to try to understand what Pandas does in the default case. I'll guess, but some editorial work on your part may be required. :)

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On Fri, Mar 13, 2020 at 6:16 AM Tom Augspurger ***@***.***> wrote: Can you submit a PR improving the documentation? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#32664 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMVDVLN3A2GNS5SLKDHZULRHIW2FANCNFSM4LGR4ENQ> .

[steve-the-bayesian]

I tried adding the following text: but I don't know how to PR into the pandas github repo. Here is my suggestion: The default value of ``None`` instructs pandas to guess. If the number of fields in the column header row is equal to the number of fields in the body of the data file, then a default index is used. If it is one larger then the first field is used as an index. Please modify as needed for correctness. On Fri, Mar 13, 2020 at 9:00 PM Steven Scott <steve.the.bayesian@gmail.com> wrote:

…

I'll give it a go. Full disclosure: I was looking at the docs to try to understand what Pandas does in the default case. I'll guess, but some editorial work on your part may be required. :) On Fri, Mar 13, 2020 at 6:16 AM Tom Augspurger ***@***.***> wrote: > Can you submit a PR improving the documentation? > > — > You are receiving this because you authored the thread. > Reply to this email directly, view it on GitHub > <#32664 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ABMVDVLN3A2GNS5SLKDHZULRHIW2FANCNFSM4LGR4ENQ> > . >