Python/Pandas: Converting numbers by comma separated for thousands

Question

I have a dataframe with a column containing long numbers. I am trying to convert all the values in the numbers column to comma separated for thousands.

df

col_1      col_2
Rooney     34590927
Ronaldo    5467382
John       25647398

Answer 1

You can use string formatting,

df['col_2'] = pd.to_numeric(df['col_2'].fillna(0), errors='coerce')    
df['col_2'] = df['col_2'].map('{:,.2f}'.format)

Do remember that the col_2 now will be string not integer.

    col_1   col_2
0   Rooney  34,590,927.00
1   Ronaldo 5,467,382.00
2   John    25,647,398.00

Answer 2

apply format function to col_2

df = df.assign(col_2=df.col_2.astype(int).apply('{:,}'.format))

     col_1       col_2
0   Rooney  34,590,927
1  Ronaldo   5,467,382
2     John  25,647,398

Answer 3

d = len(list(df.columns))

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and we want to convert only 20 columns