Basic concepts of Python syntax

If you are not familiar with the practical application of the Python syntax, you can use the following articles to give a detailed introduction to the basic concepts of the Python syntax, I hope you will understand some specific applications of computer applications in the following articles.

Although the Python syntax is very concise, I have sorted out some basic points.

Basic Concepts

1. Number: integer, long integer, floating point number example: 3.23 or 52.3E-4, plural: (-5 + 4j) or (2.3-4.4.7 )]

2. String:

1) the strings in double quotes are exactly the same as those in single quotes.

2) using three quotation marks (') or "], you can indicate a multi-line string.

3) Escape Character \], but a separate backslash at the end of a string line is used to continue the line

4) Natural string: The character string is specified by adding the prefix r or R, so that it is not escaped as it is)

5) Unicode string: prefix u or U before the string, for example, u. This is unicode. <o: p> </o: p>

3. variables: when using variables, you only need to assign them a value. No need to declare or define data types

4. identifier: uppercase or lowercase letters), underscore '_', or number 0-9), and the first character must be an uppercase or lowercase letter) or underscore '_')

5. indent: In the Python syntax, statement blocks are marked in indentation instead of braces. That is, statements at the same level must have the same indentation.

6. Operators)

(1) power operator **: x ** y returns the y Power of x. For example, 3 ** 4 = 3*3*3*3*3.

(2) Remove the integer part of the operator //: returns the integer part of the operator. For example, 4 // 3.0 returns 1.0.

(3) Boolean "Non" operator not

(4) Boolean "and" operator and

(5) Boolean "or" operator or

7. Control Flow

(1) if statement: the form is as follows: (Note that the if statement contains a colon at the end, telling the Python syntax to follow a statement block; and there is no switch statement)

 
 

  
  
if condition:  
  
  
statement  
  
  
elif condition:  
  
  
statement  
  
  
else  
  
  
statement   
 
 

(2) while statement: the form is as follows:

 
 

  
  
while condition:  
  
  
statement  
  
  
else:  
 
 

(3) for statement: the form is as follows:

 
 

  
  
for element in collection:  
  
  
statement  
  
  
else:   
 
 

(4) break statement: similar to other languages, it should be noted that if it is terminated from the for or while LOOP, no corresponding loop else block will be executed

(5) continue statement: same as other languages

8. function: defined by the def keyword. The def keyword is followed by the identifier name of a function, followed by a pair of parentheses. Variable names can be included in parentheses, which end with a colon. Next is a sentence, which is a function body, for example:

 
 

  
  
def function_name():  
  
  
statement  
 
 

9. module: a module is a python file. It is generally a tool set or reusable code, similar to the tool class in C.