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

Question

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 1

In awk

Will work if the string matches any field.

awk 'FNR==NR{a[$1]++;next}{for(i=1;i<=NF;i++)if(a[$i]){print;next}}' file{1,2}

a a1
b b1

For edit

awk 'FNR==NR{a[$1]++;next}{for(i=1;i<=NF;i++)if(a[$i]){for(j=1;j<=a[$i];j++)print;next}}' file{1,2}

a a1
a a1
b b1

Answer 2

这终于可以了。

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

Answer 3

If files are not large, just do

dpo1 = [i.strip() for i in dpo1]
lines = [i.strip() for i in dpo2 if(any([j for j in dpo1 if j in i]))]
>>>lines
['a a1', 'b b1']
>>>for i in lines:
...    print i

'a a1'
'b b1'

Answer 4

f1=open("file1")
f2=open("file2")
dpo1=f1.readlines()
dpo2=f2.readlines()
for x in dpo2:
    for y in dpo1:
        if y.strip() in x:
            print x.strip()
            break

For each line in dpo2(source file, which generate the outputs), test if it contains one of line in dpo1(conditional file). If we get a match, print it and break for next line in dpo2.