How to insert a character every nth character in a pandas dataframe column

February 22, 2022

One column of my dataframe contains mac addresses without colons.
I would like to add a colon to every mac address after every 2nd character.

I was looking for a split every nth character option of pd.Series.split.str() so that I could split the mac address in six and concat afterwards but according to the documentation splitting on number of characters is not available. There is the regex option, but regex is not a skill I have.

I assume there is an even easier solution than splitting and concatting but I have not come across that.

Help would be much appreciated, thank you.

      mac_address
0     0003E6A584C2
1     0003E6A584CC
2     0003E6A584DA
3     0003E6A584DC
4     0003E6A584E4

>Solution :

Let us try findall with map (.. means N = 2)

df.mac_address.str.findall('..').map(';'.join)
Out[368]: 
0    00;03;E6;A5;84;C2
1    00;03;E6;A5;84;CC
2    00;03;E6;A5;84;DA
3    00;03;E6;A5;84;DC
4    00;03;E6;A5;84;E4
Name: mac_address, dtype: object