DOC: section in indexing user guide to show use of np.where #37839
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ivanovmg
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Nov 14, 2020
jreback
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Nov 14, 2020
| Setting with enlargement conditionally using :func:`numpy` | ||
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| An alternative to :meth:`~pandas.DataFrame.where` is to use :func:`numpy.where`. |
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What is the difference compared to using DataFrame.where ?
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Hi Joris, with np.where, enlarging the dataframe by adding a column is straightforward. Also, it naturally extends to multiple conditions with np.select.
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@suvayu thanks for the answer! Looking at the example now, I think the main difference is that with np.where, your x/y values to take from don't need to be a Series to start with (eg Series.where always takes the values from the calling Series where the condition is True, and so indeed you wouldn't be able to achieve the actual example here)
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thanks @suvayu |
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black pandasgit diff upstream/master -u -- "*.py" | flake8 --diffAdd a section in the user guide to illustrate the use of
np.whereandnp.selectto enlarge a dataframe conditionally. The example is taken from SO, as mentioned in this issue.