I want to sum numbers in multidimentional array using recursion in Python:
tab = [7, 5, [3, 6, [2]], 7, [1, [2, 3, [4]], 9, 2], 4]
I have tried few things, for example this:
sum(map(sum, tab))
It works for simple arrays, e.g. [[1, 2], [3, 4]], but it doesn't work for the one on top. I get this error:
TypeError: 'int' object is not iterable
Any ideas please?
One way to do it:
tab = [7, 5, [3, 6, [2]], 7, [1, [2, 3, [4]], 9, 2], 4]
def r_sum(tab):
return sum(r_sum(item) if isinstance(item, list) else item for item in tab)
r_sum(tab)
# 55
You can use the following recursive algorithm:
tab = [7, 5, [3, 6, [2]], 7, [1, [2, 3, [4]], 9, 2], 4]
def sumLst(l):
sum = 0
for ele in l:
if type(ele) in [float, int]:
sum += ele
else:
sum += sumLst(ele)
return sum
print(sumLst(tab))
if isinstance(ele, (float, int)) is neater here. Also I think you just need to check if ele is a list in this case, then you recurse if it is.
type(ele) in [float, int] more readable, since with isinstance(ele, (float, int)) I always assume on first sight that you want to check against a tuple. However in case you prefer feel free to use your statement. There is no real argument against it ;)