Find all indexes of zero in an array-CodePudding

Input: array=[3, 4, 7, 0, 2, 3, 0, 6, 3, 0] or any integer array. Output: 3, 6, 9

    arr = [1,0,2,3,0,4,5,0]
    item = 0
    index1 = arr.index(item)
    start1=(index1 1)
    index2 = arr.index(item,start1)
    start2=(index2 1)
    index3 = arr.index(item,start2)
    print(index1)
    print(index2)
    print(index3)

I don't know how to find the index except for the index. Help those to do so that would find all the indexes of zero.

CodePudding user response：

I would suggest something like this:

arr = [1,0,2,3,0,4,5,0]
indexes = [] # list which contains the indexes of zeros
for i, v in enumerate(arr): # Iterate over indexes and values (i and v)
    if (not v): # Equivalent to if (v == 0) in the case of an integer array
        indexes.append(i)

At the end you will have in indexes all the indexes of the zeros of arr:

>>> indexes
[1, 4, 7]

I would suggest you to read the documentation about enumerate to better understand the code.

CodePudding user response：

This can be done with a generator as follows:

array = [3, 4, 7, 0, 2, 3, 0, 6, 3, 0]

print(', '.join(str(i) for i, v in enumerate(array) if v == 0))

Output:

3, 6, 9