Creating a counter inside a Python for loop

Question

Obviously, if we do this, the counter will remain at 0 as it is reset at the start of every iteration:

for thing in stuff:
    count = 0
    print count
    count =+1
    write_f.write(thing)

But as I have this code inside of function, it does not work to do this either:

count=0
for thing in stuff:
    print count
    count =+1
    write_f.write(thing)

I have several different indent levels, and no matter how I move count=0about, it either is without effect or throws UnboundLocalError: local variable 'count' referenced before assignment. Is there a way to produce a simple interation counter just inside the for loop itself?

Not true. Your second code works fine (apart from the typo Johnny points out). You need to show the actual code and error. — Daniel Roseman, Dec 01 '16 at 14:54
You could also use `enumerate`. `for count, thing in enumerate(stuff):` — Shaun, Dec 01 '16 at 14:54

daniel451 · Accepted Answer · 2016-12-01T15:01:18.340

This (creating an extra variable before the for-loop) is not pythonic .

The pythonic way to iterate over items while having an extra counter is using enumerate:

for index, item in enumerate(iterable):
    print(index, item)

So, for example for a list lst this would be:

lst = ["a", "b", "c"]

for index, item in enumerate(lst):
  print(index, item)

...and generate the output:

0 a
1 b
2 c

You are strongly recommended to always use Python's built-in functions for creating "pythonic solutions" whenever possible. There is also the documentation for enumerate.

If you need more information on enumerate, you can look up PEP 279 -- The enumerate() built-in function.

This is the same information as the linked duplicate. It should've just been closed as a duplicate. — Morgan Thrapp, Dec 01 '16 at 15:36

Creating a counter inside a Python for loop

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