I need to sum objects (strings, ints, etc.) in one function (don't create other function, it can be done within one). It should work this way: When given my_sum([[['s'],'ta'],['c',['k']]]), it should return 'stack'.
I came up with this:
def my_sum(array):
if not array: #empty array
return None
else:
for item in array:
if type(item) == list:
my_sum(item)
else:
print(item)
It of course is not doing what it should be, I was just playing around with it trying to come up with something. This code above returns this:
s
ta
c
k
I think I am not that far from result as I have what I need, but here is the problem how can I sum up those items ? I can't write result = '' anywhere in the function and then return it, because it would be deleting every time there would be recursion call. Also I don't want global variables (if anyone would think of that). Maybe I am just being stupid and can't see that it is one simple thing, pardon me if it is so.
Thank you for every answer!
The common accumulating pattern is:
result = <init value>
for item in argument:
result = result <operator> item
return result
(this can be written more concisely, but that's not the point for now).
Applied to your problem:
def my_sum(items):
result = ''
for item in items:
if type(item) == list:
result += my_sum(item)
else:
result += item
return result
Note that type(x) == y is frowned upon in Python, isinstance is considered better style.
Homework: extend the function so that it works for these arguments too:
print my_sum([[['s'],'ta'],('c',('k')), {('over'), ('flow')}])