Using a dictionary to replace values but error - pandas data frame

Asked May 29 '22 at 06:38

Active May 29 '22 at 22:48

Viewed 42 times

-1

I am trying to replace values. My dictionary is

 apple=fruit
 tomato=vegetable
 steak=protein
 milk=dairy

trying to change this col1

col1       ->     col1
apple             fruit
apple             fruit
tomato            vegetable
steak             protein
milk              dairy

When I try the code I am getting an error message?

d = {'apple': 'fruit', 
     'tomato': 'vegetable', 
     'steak': 'protein', 
     'milk': 'dairy'}

df[col1]=df.col1.map(d)

any help?

edit

 df['col1']=df['col1'].map(d)

the values here aren't being saved to the pandas dataframe

edited May 29 '22 at 22:48

asked May 29 '22 at 06:38

OptimusPrime

1

You haven't shown us the error message. Without your data we can't run the code to see it for ourselves. Please don't ask us to guess what it might be. – BoarGules May 29 '22 at 06:45
1

Perhaps you meant `df['col1']=df.col1.map(d)`? – Nick May 29 '22 at 06:47
it doesn't save the values, what am i doing wrong? – OptimusPrime May 29 '22 at 22:47
@Nick it doesn't save the mapped value to the existing coumn. do you know what is wrong? – OptimusPrime May 30 '22 at 03:34
@OptimusPrime works for me: https://ideone.com/xLr3eI – Nick May 30 '22 at 03:39
@Nick I see my actual df has more rows than the mapping file. so values that don't have a corresponding map value are changed to NaN. How do I fix this? – OptimusPrime May 30 '22 at 14:52
@OptimusPrime see https://ideone.com/t8hpIJ I've vtc'd this with a dupe (see the second answer), you should accept that. – Nick May 30 '22 at 23:14

0 Answers0