为什么Python在if语句中将字符串/数字评估为True还是myNumber == True返回False？

Question

The following will print 'ok' :

if 5:
   print('ok')

Yet when I do:

print(5 == True) 

The output is False .

The same thing happens with strings. Why?

Answer 1

You're testing different things here.

The if just checks if the bool of the expression (see also "Truth value testing" ) is True not if the identity is equal to True .

So what is actually tested by the if is:

>>> bool(5) == True
True

Answer 2

True has value 1. If you set True = 5 (only in python 2) the equality become True. The 'if' statement is like it is checking if the guard is not 0 or None so every number not 0 is ok to enter in the first block. In fact False has value 0.