python - Create pandas dataframe column from another column that has dictionary keys -

i have dataframe , dict. these like,

import pandas pd df1 = pd.dataframe({'first':['john','oliver','sarah']}) df1_map = {'john': 'anderson', 'oliver': 'smith', 'sarah' : 'shively'} print (df1) print (df1_map)      first 0    john 1  oliver 2   sarah {'oliver': 'smith', 'sarah': 'shively', 'john': 'anderson'} 

the values of df1['first'] represent key values of dict.

i add second column data frame called df1['second'] dict relationship maintained following dataframe,

    first    last 0    john  anderson 1  oliver     smith 2   sarah   shively 

now, iterate on dataframe values, so,

df1['last'] = [ df1_map[i] in list(df1['first'])] 

i wondering if pandas support vectorized implementation / function can without iterating on rows of df

you can map dictionaries values directly keys with:

df1['last'] = df1['first'].map(df1_map) 

result is:

out[6]:      first      last 0    john  anderson 1  oliver     smith 2   sarah   shively