Error using conditional values in pandas dataframe

Question

I am trying to use the following code to set a new column, wdf['Thunder'] to the value of wdf['RngT] if the word Thunderstorm is in the column wdf['Notes']. However, I keep getting the error TypeError: argument of type 'float' is not iterable. None of the columns are floats. RngT is an int, Notes is an object. Full code is:

wdf['Thunder'] = [wdf['RngT'] if 'Thunderstorm' in x else 0 for x in wdf['Notes']]

New to pandas, so would appreciate any insight.

Thanks!

cs95 · Accepted Answer · 2018-05-08 00:06:10Z

1

You may consider a performant alternative, np.where:

wdf['Thunder'] = np.where(
    wdf['Notes'].astype(str).str.contains('Thunderstorm'), wdf['RngT'], 0
)

Note that your first approach probably didn't work because your column was mixing strings and floats. Using astype(str) before checking for containment should fix that.

edited May 8, 2018 at 0:06

answered Mar 5, 2018 at 20:51

cs95

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