.all() on pandas series not return expected behavior-CodePudding

I have a dataframe called df_output like so

index  col1
0    | ''
1    | ''
2    | ''
3    | ''
4    | ''

If I run df_output['col1'].values.all() == '' my return value is true. However if I edit the dataframe so it looks like this

index  col1
0    | '324'
1    | ''
2    | ''
3    | ''
4    | ''

And run df_output['col1'].values.all() == '' I still get a return value of true. Shouldn't this line return false, since the value at index 0 for col1 is '324'? Or am I misunderstanding how .all() works on a series.

CodePudding user response：

df_output['col1'] == '324' will give you a per-row comparison with '342' resulting in a Series of True/False. Then you reduce those True/False into one with (df_output['col1'] == '324').all() which will be False for both of your example dataframes. However, (df_output['col1'] == '').all() should give you a True for your first dataframe.