CODEWITHSUNDEEP
pythonlistloopsiteration
ProSagramor
ProSagramor

Reputation: 41

How can I skip specific iterations in a for loop?

Basically, I have a nested for loop. In the inner loop, something happens, and I can skip 3,4,5 or however many iterations i need skipped. But I can't do the same for the outer loop. Hope that made sense. Here is my code:

phraseArray = []
phraseArray2 = []
counterAdd = 0
counter = 0

try:
    for i in range(len(wordArray)):
        for j in range(len(wordArray2)):
            if wordArray[i]==wordArray2[j]:
                counter = 0
                counter2=3
                while True:
                    if wordArray[i+counter]==wordArray2[j+counter]:
                        counter = counter+1
                        if counter==3:                                           
                            phraseArray.append(wordArray[i+0])
                            phraseArray.append(wordArray[i+1])
                            phraseArray.append(wordArray[i+2])
                        elif counter>3:
                            phraseArray.append(wordArray[i+counter2])
                            counter2 = counter2+1
                    else:
                         phraseArray.append(" ")
                         j=j+counter
                         break

except IndexError:
    print phraseArray2

The j = j+1 is used to skip certain iterations. I cant do the same for the outer loop because the inner loop changes the counter variable which dictates how many iterations need to skipped. Any suggestions?

Thanks in advance guys! :)

Upvotes: 3

Views: 1485

Answers (3)

mgilson
mgilson

Reputation: 309821

I'd work with iterators here.

import itertools

def skip(iterable, n):
    next(itertools.islice(iterable, n, n), None)

outer_numbers = iter(range(...))
for i in outer_numbers:
    inner_numbers = iter(range(...))
    for j in inner_numbers:
        if condition:
            skip(outer_numbers, 3)  # skip 3 items from the outer loop.
            skip(inner_numbers, 2)  # skip 2 items from the inner loop.

Of course, you may want/need continue and/or break statements.

Upvotes: 3

Wabonano
Wabonano

Reputation: 128

You can't use "break" in the outer loop because this will finish the loop and not skip it, what you can do is use some IF statements to control the cases you want. something like

if(condition=skip):
   #do nothing
else:
  # do

Upvotes: 2

recursive
recursive

Reputation: 86064

A general form for skipping multiple iterations of a loop could work like this.

skips = 0
for x in y:
    if skips:
        skips -= 1
        continue

    #do your stuff

    #maybe set skips = something

Upvotes: 3

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