Python learning log for small y-data type (if loop)

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The following information is compiled from the (1) Liaoche python tutorial http://www.liaoxuefeng.com/wiki/001374738125095c955c1e6d8bb493182103fac9270762a000

(2) Concise python tutorial http://woodpecker.org.cn/abyteofpython_cn/chinese/

1. Process Control

(1) If statement

1) The If statement contains a logical expression, using an expression comparison, to make a decision based on the results of the comparison.

2) If expression:

Statement (s)

Note: Python uses indentation as a method of grouping its statements, and it is recommended to use 4 spaces instead of indents

3) The logical value (BOOL) is used to denote such concepts as: Right and wrong, true and false, empty and non-empty.

The logical value consists of two values:

True: Indicates non-empty quantities (e.g. string,tuple,list,set,dictonary, etc.), all non-zero

False: Indicates 0,none, empty amount, etc.

Function: Mainly used in interpreting sentences for judging

Whether a string is empty

Whether the result of an operation is zero

Whether an expression is available

(2) Else statement:

If expression:

Statement (s)

Else

Statement (s)

If the conditional expression if statement resolves to a value of 0 or FALSE, the Else statement is executed.

Else statement is an optional statement that cannot be used alone and can have at most one else statement

(3) elif statement:

If expression:

Statement (s)

Elif expression2:

Statement (s)

Elif Expression3:

Statement (s)

Else

Statement (s)

The Elif statement can check that multiple expressions are true and executes a block of code, and the Elif statement is optional. There can be any number of elif statements.

Python learning log for small y-data type (if loop)