Python and-or skills

Python and-or skills

Similar expressions in C language:Bool?A:BIf the expression value is true, the value is a, otherwise it is B.

Let's look at an example:

>>> A = "first" >>> B = "second" >>> 1 and a or B 'first '>>> 0 and a or B 'second'

This example is well understood. 1 indicates true, the value is a, otherwise it is B.

This is not the case during use. If expression a is false, the expression value is B.

For example:

>>> A = "" >>> B = "second" >>> 1 and a or B 'second'

There is a skill to avoid the above problems, as shown below:

>>> A = "" >>> B = "second" >>> (1 and [a] or [B]) [0]

Because [A]Is a non-empty list, it will never be false. Even AYes 0Or ''Or other false values, list [A]True because it has an element.