Error replacing values in a column using pandas

Question

I am trying to replace the values in a column with numbers. These are the unique values in the column:

['R2' '01' '02' 'C1']

So I did this

data = pd.read_csv('file.csv')
df = pd.DataFrame(data)

df['rates'].apply({'R2': 1, '01' : 2, '02' : 3, 'C1' : 4}.get)

But when I try to print out df['rates'] after the supposed replacement, I still got same values:

['R2' '01' '02' 'C1']

This is how my file.csv looks like

amount,id,rates,height
1400,4,R2,3
1389,6,R2,8
10000,1,01,13

Can you provide code to produce your series? That looks like it should work. — piRSquared, Sep 15 '18 at 23:31
You also need to show the contents of the file. Only first few lines. — piRSquared, Sep 15 '18 at 23:35
Ohh. I think I know/crosses fingers. Apply doesn’t change the dataframe. You need to assign back to column — piRSquared, Sep 15 '18 at 23:40

U13-Forward · Accepted Answer · 2018-09-15T23:33:15.627

1

Try map:

df['rates'].map({'R2': 1, '01' : 2, '02' : 3, 'C1' : 4},inplace=True)

Or:

df['rates'] = df['rates'].map({'R2': 1, '01' : 2, '02' : 3, 'C1' : 4})

Actually your code works but need to assign:

df['rates']=df['rates'].apply({'R2': 1, '01' : 2, '02' : 3, 'C1' : 4}.get)

edited Sep 15 '18 at 23:33

answered Sep 15 '18 at 23:24

U13-Forward

Its the same thing. It didn't work. df['rates'].map({'R2': 1, '01' : 2, '02' : 3, 'C1' : 4}) print df['rates'] – shekwo Sep 15 '18 at 23:31
@radioactive Edited mine – U13-Forward Sep 15 '18 at 23:33
1

Oh thanks. It works, I needed to assign – shekwo Sep 15 '18 at 23:43
@radioactive happy that i helped, – U13-Forward Sep 16 '18 at 00:29

1 Answers1