sort a column's values alphabetically-CodePudding

Hi I have a pandas dataframe with multiple columns in that I have a object type column in which values are seperated by ','. I want to sort the column's values in alphabetical order.

The dataframe I have :

ID    things
1     pen,car,robot
2     lamp,jug,phone
3     switch,pen,book

The dataframe I want:

ID    things
1     car,pen,robot
2     jug,lamp,phone
3     book,pen,switch

Thanks in advance.

CodePudding user response：

Split, sort and then join:

df['things'] = df.things.apply(lambda x: ','.join(sorted(x.split(','))))

df
   ID           things
0   1    car,pen,robot
1   2   jug,lamp,phone
2   3  book,pen,switch

A little benchmark against .str method:

timeit("df.things.apply(lambda x: ','.join(sorted(x.split(','))))", number=10000, globals=globals())
4.744999999995343

timeit("df['things'].str.split(',').map(np.sort).str.join(',')", number=10000, globals=globals())
14.570999999996275

CodePudding user response：

You can split with str.split(), sort with .map() numpy.sort() and join back the texts with str.join(), as follows:

df['things'] = df['things'].str.split(',').map(np.sort).str.join(',')

All functions used are fast vectorized Pandas/numpy functions.

Result:

print(df)


   ID           things
0   1    pen,car,robot
1   2   lamp,jug,phone
2   3  switch,pen,book