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I'm trying to identify when a "date" (been converted to an integer for this) is greater than 30, and if so, if there is another date for that individual that has a frequency of greater than 1 (at least 2) and if these are true I want to put the "top" date (the one that appeared the most of times) into a new column, but I'm running into an error.

for index_label, row_series in describe_crt.iterrows():
    if (describe_crt["delta_days_post_crt"] != 0) & (describe_crt["delta_days_post_crt"] > 30) & (describe_crt["freq"] > 1):
        describe_crt.at[index_label , "best_crt_date"] = describe_crt["top"]```


> ValueError                                Traceback (most recent call
> last)  <ipython-input-108-9cc36c985dca> in <module>
>       7 # iterate over the dataframe row by row
>       8 for index_label, row_series in describe_crt.iterrows():
> ----> 9     if (describe_crt["delta_days_post_crt"] != 0) & (describe_crt["delta_days_post_crt"] > 30) & (describe_crt["freq"] >
> 1):
>      10         describe_crt.at[index_label , "best_crt_date"] = describe_crt["top"]
>      11 
> 
> ~/opt/anaconda3/lib/python3.7/site-packages/pandas/core/generic.py in
> __nonzero__(self)    1553             "The truth value of a {0} is ambiguous. "    1554             "Use a.empty, a.bool(), a.item(),
> a.any() or a.all().".format(
> -> 1555                 self.__class__.__name__    1556             )    1557         )
> 
> ValueError: The truth value of a Series is ambiguous. Use a.empty,
> a.bool(), a.item(), a.any() or a.all().
thirdDeveloper
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jjohnson12
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    hi @jjohnson12, i'd suggest u use pandas/numpy's vectorised methods as they are faster than the if/else pattern from python. this also means avoiding iterrows. also, kindly share a sample of ur data, with ur expected output. Use [this](https://stackoverflow.com/questions/20109391/how-to-make-good-reproducible-pandas-examples) as a guide. – sammywemmy Mar 29 '20 at 01:09
  • Please provide a [mcve]. – AMC Mar 29 '20 at 01:16

0 Answers0