pandas dataframe return first word in string for column

Question

I have a dataframe:

df = pd.DataFrame({'id' : ['abarth 1.4 a','abarth 1 a','land rover 1.3 r','land rover 2',
                           'land rover 5 g','mazda 4.55 bl'], 
                   'series': ['a','a','r','','g', 'bl'] })

I would like to remove the 'series' string from the corresponding id, so the end result should be:

Final result should be 'id': ['abarth 1.4','abarth 1','land rover 1.3','land rover 2','land rover 5', 'mazda 4.55']

Currently I am using df.apply:

df.id = df.apply(lambda x: x['id'].replace(x['series'], ''), axis =1)

But this removes all instances of the strings, even in other words, like so: 'id': ['brth 1.4','brth 1','land ove 1.3','land rover 2','land rover 5', 'mazda 4.55']

Should I somehow mix and match regex with the variable inside df.apply, like so?

df.id = df.apply(lambda x: x['id'].replace(r'\b' + x['series'], ''), axis =1)

Answer 1

Use str.split and str.get and assign using loc only where df.make == ''

df.loc[df.make == '', 'make'] = df.id.str.split().str.get(0)

print df

               id    make
0      abarth 1.4  abarth
1        abarth 1  abarth
2  land rover 1.3   rover
3    land rover 2   rover
4    land rover 5   rover
5      mazda 4.55   mazda