Do x after y increment [duplicate]

Question

I want to do something after i is 20, 40, etc.

For example:

i = 0 while True: i+=1 if i == # increment of 20 (40, 60, 80, etc.): # do this

for i in range(20, x, 20): where x is at what value you want to stop (assuming you don't do anything else when the condition isn't true) — Ted Klein Bergman
– Ted Klein Bergman, Commented Aug 28, 2020 at 20:41

Aviv Yaniv · Accepted Answer · 2020-08-29 09:06:46Z

Options 1 & 2 uses the modulus operator, to detect when i is a multiplication of 20, are less efficient as unnecessary iterations will happen.

Option 3 uses range, and more efficient as only necessary iterations will happen.

Option 1

Use not i % 20:

i = 0 while True: i+=1 if not i % 20: print(i)

Option 2

Use 0 == i % 20:

i = 0 while True: i+=1 if 0 == i % 20: print(i)

Option 3 : For Loop

Using range: start from 20 till threshold in jumps of 20

threshold = 10000 for i in range(20, threshold, 20): print(i)

user13959036 · Accepted Answer · 2020-08-28 20:42:21Z

i = 0 while True: i+=1 if i % 20 == 0: # increment of 20 (40, 60, 80, etc.): print(i) #or something else

Output:

20 40 60 80 ...

2 Answers 2