Python: For Loop Looping Too Much Or Too Little

Question

My program seems to be looping several times here despite a break:

for sequence in qwerty:
    for char in range(0,passlen):
        if password [char : char + 2] in sequence:
           score -= 5
           print(score,"subtracting 5")

It usually outputs this:

38 subtracting 5
33 subtracting 5
28 subtracting 5
23 subtracting 5
18 subtracting 5
13 subtracting 5
8 subtracting 5
3 subtracting 5
-2 subtracting 5
-7 subtracting 5

Or nothing at all.

It should only loop equal to the number of 3 letter QWERTY sequences in password.

What should I do to mediate this?

You are breaking only one loop, however, you have 2. The outer loop triggers your inner loop on next iteration — Adelin, Jan 30 '18 at 09:26
Why is your title `while loop` when you clearly have `for loop`? — Adelin, Jan 30 '18 at 09:27
Possible duplicate of [How to break out of multiple loops in Python?](https://stackoverflow.com/questions/189645/how-to-break-out-of-multiple-loops-in-python) — llllllllll, Jan 30 '18 at 09:27
this may help `break` a nested loop: https://stackoverflow.com/a/3150107/4954037 — hiro protagonist, Jan 30 '18 at 09:29

score 0 · Answer 1 · answered Jan 30 '18 at 09:29

The break only breaks the inner-most loop (i.e. for char in range(0,passlen):) so you go back to the outer loop and move on.

You can use a flag instead:

flag = False
for sequence in qwerty:
          if flag: # False until the inner loop breaks
               break
          for char in range(0,passlen):
            if password [char : char + 2] in sequence:
               score -= 5
               print(score,"subtracting 5")
               flag = True
               break

score 0 · Answer 2 · answered Jan 30 '18 at 09:31

0

the outer for loops seems redundant in this program. The continued looping you refer is the "for sequence in qwerty:", you should either 1) delete the outer for loop or 2) add a break statement for the outer loop

answered Jan 30 '18 at 09:31

Nicholas

21
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Python: For Loop Looping Too Much Or Too Little

2 Answers2