How to get all lines from one file which contain a string in another file?

File 1:

a
a
b
c
d

File 2:

a a1
b b1
e e1
f f1

My desired output:

a a1
a a1
b b1

I am trying to implement this using bash or Python.

In python I tried:

f1=open("file1")
f2=open("file2")
dpo1=f1.readlines()
dpo2=f2.readlines()

for i in dpo2:
    for j in dpo1:
        if j in i:
            print i

In bash I was thinking of using grep but grep will give the output that matches the entire line but this is not the case here. Any ideas?

Answer

This is what works finally.

awk 'NR==FNR{a[$1]=$2;next}$0 in a{print $0,a[$0]}' file2 file1