Vectorizing A For Loop In Python

I'm a newbie to python and had a question to ask about vectorizing a code def makeNames2(nList): for nLi in nList: nLIdx=[i for i,j in enumerate(nList) if j==nLi] if nLId

Solution 1:

nLTest, items = ['asda','asda','test','ada','test','yuil','test'], {}
for idx, item inenumerate(nLTest):
    nLTest[idx] += str(items.setdefault(item, 0) or"")
    items[item] += 1print nLTest

Output

['asda', 'asda1', 'test', 'ada', 'test1', 'yuil', 'test2']

Solution 2:

You could simplify it a bit:

def makenames(lst):
    seen = {}
    for index, name in enumerate(lst):
        if name in seen:
            seen[name] +=1
            lst[index] = "{0}{1}".format(name, seen[name])
        else:
            seen[name] = 0return lst

This removes one of the for loops, operating in O(n) (dictionary access is O(1)).

Note that this modifies the list in-place; you may wish to have a new output list to append to instead. You could also simplify this slightly using defaultdict or Counter from the collections module.

Solution 3:

This is arguably more readable, avoids O(n^2). It's also not in-place.

from collections import defaultdict
defmakeNames3(nList):
    counter= defaultdict(lambda:0)
    defposfix(x):
        n= counter[x]
        counter[x]+=1returnstr(n) if n>0else""return [x+posfix(x) for x in nList]