How would a range work if the starting point and ending points are the same in Python-CodePudding

I am relatively new to coding and saw this question on a video. enter image description here

Like for the

for i in range(2, num):

line I understand how it would work when plugging in a number 3 or greater for the variable num but I do not understand how it would work if it were to be 2.

The code checks if it is a prime number, so if I plug in 2 it would be:

for i in range (2,num-1):

which is

for i in range (2,1):

How would the code still run?

CodePudding user response：

A range(start, stop) is a half open interval from start to but exluding stop. See range for the details. The range may be empty as would be the case for your example of range(2,1), note, however there is also a step argument if you want the range to down instead of up range(2, 1, -1) which in this case would evaluate to 2.

CodePudding user response：

The range will be empty and it will simply skip the for loop.

Not much unlike this:

empty_list = []
for item in empty_list:
   print("I love pumpkin") # will never run