python: running a loop over indexes of a sub list

Question

for items in things:
    while inputFloat != 0:
        thingsBack[][1]=inputFloat//things[]
        inputFloat=inputFloat-(things[]*thingsBack[][1])

things is a list of n elements, while thingsBack is a list with n sub-lists. I want both things and thingsBack to start at the 0th element and to loop through the recursion. The calculation inputFloat//things[] only changes the 1 index of the j-th sublist in thingsBack. i know [] is invalid syntax, but used for illustrative purposes.

it seems like there would be an obvious solution, but I am not seeing it.

Can you add sample inputs? and your expected output maybe? Your question a little unclear like this. — Lafexlos, Jan 27 '16 at 07:10
Also, if `inputFloat` is actually a float then it's highly unlikely it will ever be _exactly_ zero. [Is floating point math broken?](http://stackoverflow.com/questions/588004/is-floating-point-math-broken) — Lafexlos, Jan 27 '16 at 07:11

score 2 · Answer 1 · edited May 23 '17 at 10:27

2

Taking a guess, I think you are looking for the index of the current item in your for loop?

for index, items in enumerate(things):
    # do stuff using index

Check this out:

Accessing the index in Python 'for' loops

edited May 23 '17 at 10:27

Community

1
1

answered Jan 27 '16 at 08:39

Maximus

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score 0 · Answer 2 · answered Jan 27 '16 at 08:45

You can use several different approaches

A range based for loop

for i in range(len(things)):
    thingsBack[i][1] = inputFloat // things[i]
    # etc.

Loop over the elements of things using enumerate, to also get the index

for i, thing in enumerate(things):
    thingsBack[i][1] = inputFloat // thing
    # etc.

Loop over a zipped list of things and thingsBack

for thing, thingBack in zip(things, thingsBack):
    thingBack[1] = inputFloat // thing
    # etc.

python: running a loop over indexes of a sub list

2 Answers2