Convert comma-separated values into integer list in pandas dataframe

How to convert a comma-separated value into a list of integers in a pandas dataframe?

Input:

Desired output:

Answer

There are 2 steps – split and convert to integers, because after split values are lists of strings, solution working well also if different lengths of lists (not added Nones):

df['qty'] = df['qty'].apply(lambda x: [int(y) for y in x.split(',')])

Or:

df['qty'] = df['qty'].apply(lambda x: list(map(int, x.split(','))))

Alternative solutions:

df['qty'] = [[int(y) for y in x.split(',')] for x in df['qty']]
df['qty'] = [list(map(int, x.split(','))) for x in df['qty']]