Python if statment's results into pandas dataframe

Question

I am trying to create a DataFrame from a simple if statement result with no success. Could you show me the right method, please? This is what I have so far but the value of discrep is not added to the DataFrame.

discrepancy_value=round(system_availability.iloc[0,0]-data_av.iloc[0,0],2)
discrep=[]
if discrepancy_value>1:
    discrep=discrepancy_value
else:
    discrep=r'Discrepancy is not significant'
discrepancy=pd.DataFrame()
discrepancy['Discrepancy']=discrep

score 4 · Accepted Answer · answered Nov 21 '19 at 12:52

Your problem is, that you are trying to insert a single value in the dataframe. The dataframe needs lists, not values. What you should be doing is:

discrep=[]
if discrepancy_value>1:
    discrep.append(discrepancy_value)
else:
    discrep.append(r'Discrepancy is not significant')
discrepancy=pd.DataFrame()
discrepancy['Discrepancy']=discrep

score 0 · Answer 2 · answered Nov 21 '19 at 12:53

0

On one line:

discrepancy = pd.DataFrame({'Discrepancy': [discrepancy_value if discrepancy_value > 1 else r'Discrepancy is not significant']})

answered Nov 21 '19 at 12:53

Lukas Thaler

2,672
5
15
31

thanks. i've just started python the one line version is on the next level. maybe in two weeks time :) – blooregard Nov 21 '19 at 13:17

score 0 · Answer 3 · answered Nov 21 '19 at 13:01

You are trying to set a column on an empty dataset with 0 rows. If there would be already rows in the dataframe the following would add the same value to all rows:

discrepancy['Discrepancy']=discrep

But because there are no rows in the dataframe, the column is not added to any row.

You could append a new row with the column value like this:

discrepancy.append([{'Discrepancy': discrep}])

Or add the row already when you create the dataframe

discrepancy=pd.DataFrame([{'Discrepancy': discrep}])

Python if statment's results into pandas dataframe

3 Answers3