#%%
import pandas as pd
number = ['a1','a2','a3','a4','a5','a6','a7','a8']
value = [238,234,67,234,1234,675,1234,124]
identifier = ['Bob', 'Steve', 'Jane', 'John', 'Jill', 'Andy', 'Alice', 'Liz']

df = pd.DataFrame({'num':number, 'val' : value})
xwalk = pd.DataFrame({'num':number, 'id':identifier})

df['num'].map(lambda x: xwalk.loc[xwalk['num'] == x, 'id'])