Range function in python

问题

for n in range(2,5):
    for x in range(2,n):
        print(n,x)

Gives output as:

3 2
4 2
4 3

why the value of n start from 3 not 2?

回答1:

n starts at three because range(2, 2) is empty. Maybe you really want:

for n in range(2, 5):
    for x in range(2, n + 1):
        print(n, x)

Results:

2 2
3 2
3 3
4 2
4 3
4 4

来源：https://stackoverflow.com/questions/50575700/range-function-in-python