Determine multiple indices within a list

[jacob l]

I am trying to return a list of indices for elements within another list that pass some sort of rule (as fast as possible). Currently I am doing:

Elementspassed=[elem for elem in Mylist if point > elem]

for x in Elements passed:
newlist.append( Mylist.index(x) )
Mylist[Mylist.index(x)]=[]

I want to incorporate the for loop into the previous line. I am working with extremely large matrices and this current code takes too long. I am interested in the Elementspassed matrix just to be a list of indices in which point>elem rather than the two step process i am taking.

For example:

(for points > 33)
Now: Elementspassed=[34, 35, 34, 52, 51]
newlist=[0, 3, 4, 5, 6]

Want: Elementspassed=[0, 3, 4, 5, 6]

[bvdet]

Use built-in function enumerate().

>>> import random
>>> mylist = [random.choice(range(100)) for i in range(10)]
>>> mylist
[76, 28, 54, 8, 99, 29, 23, 33, 62, 0]
>>> [i for i,n in enumerate(mylist) if n > 33]
[0, 2, 4, 8]
>>>