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How to use apply() to change data in a pandas data frame to lowercase?

I have this pandas dataframe:

         custid  age income     gen   wp   mp  lip
0           101   45   $45K    Male   No  Yes   No
1           106   40   $39K  Female  Yes  Yes  Yes
2           111   42   $46K    Male   No   No   No
3           116   43   $36K    Male  Yes  Yes  Yes
4           121   38   $59K  Female   No  Yes  Yes
5           126   55   $28K  Female   No   No   No
6           131   35   $35K    Male   No  Yes  Yes
7           136   27   $26K    Male  Yes   No   No
8           141   43   $36K    Male   No  Yes   No
9           146   41   $38K  Female  Yes  Yes   No

And what I want to do is use apply() with a function to convert all the data to lowercase. I couldn’t find anything on the internet showing how to do this, I am currently stuck with this.

def low(x):
    return x.lower()

however it gives me error that series object has no attribute lower. Any help greatly appreciated! Thanks!


That’s because column custid and age have a integer values. Integer value doesn’t have lower() function.

For example, if you want to change gen’s data to a lower case, you can implement it like below.

df["gen"] = df["gen"].apply(low)