Backward loop in Python

Question

I need to loop backwards from i=n-2 to i = 0 to code this math formula:

math formula

for i in range(n-2,0):
    X[i] = Y[i]
    for m in range(i+1,n):

        X[i] = X[i] - T[i,m] * X[m]

It doesn't work, what am I doing wrong?

All numbers from numpy arrays

range(n - 2, 0) will count up from n-2 to -1. If you want to go backwards, you should do range(n - 2, -1, -1) so it counts backwards from n-2 to 0 (the last index isn't included) — rchome
– rchome, Commented Nov 28, 2021 at 8:25

procoder35 · Accepted Answer · 2021-11-28 08:25:56Z

1

if you want to loop backward you can use the for loop like following

range(start, end, step)

the step is 1 by default. in your case, you have to specify the decrement in order the loop the work.

answered Nov 28, 2021 at 8:25

procoder35

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