Simple usage of condition judgment statements in Python, python statements

Simple usage of condition judgment statements in Python, python statements

The simplest Condition Statement:

if expression:   expr_true_suite

As shown above, if is a keyword, expression is a condition expression, and conditional expressions support multi-condition judgment. You can use the boolean operators and, or, and not to connect. expr_true_suite is a code block. if expression is true, it is executed, if a code block contains only one row, the entire Condition Statement above can be written to one row, but the readability is poor.
Conditional statements with elif and else:

if expression1:   expr1_true_suiteelif expression2:   expr2_true_suiteelif expressionN:   exprN_true_suiteelse:   none_of_the_above_suite

As mentioned above, the syntax is similar to the conditional statements in other languages. elif and else are optional.
Conditional expressions implement ternary operators:
In C/C ++, the ternary operator is as follows (when E is set, X is executed; otherwise, Y is executed )--

E ? X : Y

Ternary operator simulated by python --

(E and [X] or [Y])[0]

Implementation of python ternary operators --

X if E else Y

Let's look at several judgment instances:

>>> if 1 < x < 2:   print('True')     True 

And indicates and

Or indicates or >>> x 2 >>> if x = 2 or x = 3: print (x) 2

If B is true, return a. Otherwise, return c.

a if b else c>>> 'True' if 1 < x <2 els