## list로 있을 때 조합 구하기

```python
user = ['root', 'manager']
pass_ = ['123',
'456',
'asd',
'password',
'admin']

for u in user:
    for p in pass_:
        print('{}:{}'.format(u, p))

# root:123
# root:456
# root:asd
# root:password
# root:admin
# manager:123
# manager:456
# manager:asd
# manager:password
# manager:admin
```

## file에 존재할 때 구하기

```python
# Iterator가 모두 소비되서 그렇군..
with open('tmp/user.txt') as f_user:
    with open('tmp/pass.txt') as f_pass:
        for u in f_user:
            for p in f_pass:
                print('{}:{}'.format(u.strip(), p.strip()))

# root:123
# root:456
# root:asd
# root:password
# root:admin
# manager:123
# manager:456
# manager:asd
# manager:password
# manager:admin
```