Question

Could someone please explain what this code exactly means:

for i,j in [(i,j) for i in range(len(rows)-2,-1,-1) for (j) in range(i+1)]:

When there is an array called rows. what would is assign to i and j?

I believe i would be the n-1th index for the array, but I’m not sure about j. Would it just be i+1?

Answer 1

[(i,j) for i in range(len(rows)-2,-1,-1) for (j) in range(i+1)]

Is the same as:

result = []
# from len(rows)-2 to 0, decrementing by one each time
for i in range(len(rows)-2,-1,-1):
       # from 0 to i        
    for j in range(i+1):
       result.append((i, j))