I have a question in prefix sum algorithm

Question

import time,random

n=int(input("put your number:"))

X=[random.randint(-999,999) for i in range(n)]

print(X)
#pr1 start
before1 = time.clock()
def prefixSum1(X, n):   # code for prefixSum1
    for i = 0 to n-1 do
        S[i] = 0
        for j = 0 to i do
            S[i]=S[i]+X[j]      
    return (S)
after1 = time.clock()
#pr2 start
before2 = time.clock()
def prefixSum2(X, n):   # code for prefixSum2
    S[0]= X[0]
    for i = 1 to n-1 do
        S[i]=S[i-1]+X[i]
    return (S)
after2 = time.clock()
#
random.seed()   
print(after1 - before1)
print(after2 - before2)

This is my code and what I am trying to make is that I randomly generate the array X from -999 to 999 and check the time of two algorithms. But whenever I run the code, it shows >

Makefile:6: recipe for target 'py3_run' failed
    make: *** [py3_run] Error 1
      File "Main.out", line 11
        for i = 0 to n-1 do
              ^

SyntaxError: invalid syntax

I have no idea what is wrong with my code. I tried to find on the internet but it seems they are the same as me...

Answer 1

Your code does not use valid python syntax for your for loops; the documentation on for statements clearly describes the syntax. In short, you need to change

for i = 0 to n-1 do

to

for i in range(n - 1):

and

for i = 1 to n-1 do

to

for i in range(1, n - 1):

You can check the documentation for range to learn about how it works.