How to remove portion of string after certain character for each element of a Pandas series (or list)?

Question

I have a Pandas series like ['AAA.B', 'BBB.C', 'CCC.D']. I want to remove the portion of each string after the period, inclusive. In other words, the desired result here would be ['AAA', 'BBB', 'CCC']. I can't figure out how to do it without iterating through each element one at a time to operate on them individually, which would be really inefficient. Any idea of how to do this?

Answer 1

Using str.split

Ex:

s = pd.Series( ['AAA.B', 'BBB.C', 'CCC.D'])
print(s.str.split(".").str[0])

Output:

0    AAA
1    BBB
2    CCC
dtype: object

Answer 2

You can use str.replace :

s = pd.Series(['AAA.B', 'BBB.C', 'CCC.D'])
s.str.replace(r'(\.\w+)', '')

0    AAA
1    BBB
2    CCC
dtype: object

Answer 3

The best way of doing this is

s = s.split('.')[0]

Another way can be regex. Or, if the part after '.'also has to be used, do

head, sep, tail = s.partition('.')

In this, head will contain the string portion before '.', sep will contain '.', and tail will contain the portion after '.'