For in don't iterate again over a file with nested loop - Python

Question

I have a users.txt and password.txt and i need to iterate in both files

Example of users.txt:

root
admin
oracle
users

Example of password.txt

toor
rooot
administrator
password

In my loop just print the first user "root" and all of the password but dont print the others users, this is my code:

fu = open("/home/dskato/diccionarios/user.txt", "r")
fp = open("/home/dskato/diccionarios/pasword.txt", "r")

for user in fu.readlines():
  for password in fp.readlines():
    print "Username: "+user+" Password: "+password

This is the output but don't iterate over the others users What it's wrong?

Username: root Password: 123456

Username: root Password: 12345678

Username: root Password: 1234

Username: root Password: pass

Username: root Password: password

And i need this output example:

root: 123456
root:password
root:toor
admin:123456
admin:password
admin:toor

Galen · Accepted Answer · 2017-12-22T21:36:39.680

3

You are iterating over all the passwords with the inner loop on the first iteration of the outer loop. On the second iteration of the outer loop, there are no more passwords to iterate (fp's current position is at the end of the file).

You could fp.seek(0) to reset fp after each user iteration:

for user in fu:
    for password in fp:
        print "Username: " + user.rstrip('\n') + " Password: " + password.rstrip('\n')
    fp.seek(0)

Or you could read the passwords once into a list:

passwords = list(fp)

for user in fu:
    for password in passwords:
        print "Username: " + user.rstrip('\n') + " Password: " + password.rstrip('\n')

There's a tradeoff between file access and memory usage here.

edited Dec 22 '17 at 21:36

answered Dec 22 '17 at 21:04

Galen

1,307
8
15

this is the output root:123, admin:pass, And i need to iterate the users again with the password, like root:123, root:pass, root:toor, admin:123, admin:pass, admin:toor – MADMVX Dec 22 '17 at 21:16
You want every user with every password? If so, please update your question to clarify. – Galen Dec 22 '17 at 21:17
Yes i need that, i edited now – MADMVX Dec 22 '17 at 21:18
no nee to use `readlines`, it is inefficient. – juanpa.arrivillaga Dec 22 '17 at 21:34
I edited my answer to reflect the updated question and incorporate feedback from @juanpa.arrivillaga. – Galen Dec 22 '17 at 21:37
This works Thanks :D @Galen – MADMVX Dec 22 '17 at 22:02

score 0 · Answer 2 · answered Dec 22 '17 at 21:10

0

You have a nested for loop, which reads passwords (in the internal loop), for each users (in the external loop).

What happened now, your external loop read first user (root), and the internal read all password, and print them together with root.

When your external loops tries to process second user, your password file is already reaching the end, nothing is printed.

You need to read lines of these files separately, store it in an array and print later.

Better yet, just use paste : https://unix.stackexchange.com/questions/234208/combining-several-files-into-a-single-csv

answered Dec 22 '17 at 21:10

wibisono

61
4

`paste` doesn't perform nested loops.It just "zips" the data together. – Jean-François Fabre Dec 22 '17 at 21:52
Indeed, I did not notice the example outputs, (or it was edited after I answered). Now trying different passwords for each users is not something I am familiar with :P – wibisono Dec 23 '17 at 06:14
same for me. Even got 2 upvotes for a wrong answer. Deleted it. – Jean-François Fabre Dec 23 '17 at 08:08

For in don't iterate again over a file with nested loop - Python

2 Answers2