Trying to run loop through a column in my data frame conditionally but not getting results I want

Question

I have a column in my df with year values as INT but some values are 0. I'm trying to run a for loop to keep the 0 values but replace the year values with a calc (i.e 2020 - value in column). So far I have:

for (i, item) in enumerate(housing['YrRenovated']):
     if item > 0:
      housing['YrRenovated'][i] = 2020 - item,
     else: 
      housing['YrRenovated'] = 0,

It runs but the max value in the column is 0 when it should be like 45

Would you kindly provide a sample input and output? Check this: https://stackoverflow.com/questions/20109391/how-to-make-good-reproducible-pandas-examples — O. Mohsen, Aug 11 '20 at 04:40
``np.where(df['YrRenovated'] > 0, 2020 - df['YrRenovated'], 0)`` — sushanth, Aug 11 '20 at 04:44

score 0 · Answer 1 · edited Aug 11 '20 at 04:41

0

try using apply and lambda functions.

housing['YrRenovated'] = housing['YrRenovated'].apply(lambda item: 2020-item if item > 0 else 0)

edited Aug 11 '20 at 04:41

Dharman

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answered Aug 11 '20 at 04:35

Faizan Naseer

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score 0 · Answer 2 · answered Aug 11 '20 at 04:48

0

Try using the following loop:

for index, row in housing.iterrows():
    if row['YrRenovated'] != 0:
        newValue = 2020 - row['YrRenovated']
        housing.at[index, 'YrRenovated'] = newValue

answered Aug 11 '20 at 04:48

O. Mohsen

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Thank you! I had the lambda function backwards! – Josh Ortega Aug 11 '20 at 14:25

Trying to run loop through a column in my data frame conditionally but not getting results I want

2 Answers2