Get row-index values of Pandas DataFrame as list?

问题:

This question already has answers here:

How do I convert a pandas Series or index to a Numpy array? (7 answers)

Closed last year.

I'm probably using poor search terms when trying to find this answer. Right now, before indexing a DataFrame, I'm getting a list of values in a column this way...

 list = list(df['column']) 

...then I'll set_index on the column. This seems like a wasted step. When trying the above on an index, I get a key error.

How can I grab the values in an index (both single and multi) and put them in a list or a list of tuples?

回答1:

To get the index values as a list/list of tuples for Index/MultiIndex do:

df.index.values.tolist()  # an ndarray method, you probably shouldn't depend on this

or

list(df.index.values)  # this will always work in pandas

回答2:

If you're only getting these to manually pass into df.set_index(), that's unnecessary. Just directly do df.set_index['your_col_name', drop=False], already.

It's very rare in pandas that you need to get an index as a Python list (unless you;re doing something pretty funky, or else passing them back to NumPy), so if you're doing this a lot, it's a code smell that you're doing something wrong.