Formatting the data of multiple columns in a dataframe

Question

I've data frame that has several columns. A couple of columns have a very large values and I want to convert those into kilo, mega, giga format (eg: 10m, 20g etc). Got a custom function to do it but kind of stuck on how to apply it for selected columns. This is what I tried:

Df:
key     avg      max
---     ---      ----
speed   100000   200000000
...


def convert(x: str):
   if int(x) <= 0:
      return 0
   .. do conversion here

df.apply(apply(lambda x: convert if x.name in ['avg', 'max'] else x)

However, this doesn't seem to be doing the conversion and also giving an error message about the data type. The following works but it has to be done for each field separately.

df['avg'] = df['avg'].apply(func)

Is there a better way to do this?

question from:https://stackoverflow.com/questions/65838363/formatting-the-data-of-multiple-columns-in-a-dataframe

Answer 1

Yes , you can do it like below:

for cols in df[['avg', 'max']].columns:
    df[cols] = df[cols].apply(function)