Python basics and its basic syntax

1. Run Python
   mode 1: Python interactive mode
   Step: cmd + Enter
   Input: python
   Input: print (“hello world”)
   Enter
   Exit: exit()
   

2. Method 2: Integrated Development Environment
   Step: print("hello world")

3. Method 3 Command line execution script
   Step python+script
   Case python hello.py

4. Basic syntax
   in Python Variable definition Python
   variable name = value
   name = Zhang San
   View variable type
   print(type(name))
   

5. Identifiers
   Some symbols and names customized by developers in the program
   Identifiers are defined by themselves, such as variable names, function names

Naming rules
for identifiers. Identifiers can only consist of letters, underscores "_", and numbers.
. Identifiers cannot start with a digit.
. Identifiers cannot use keywords
. Identifiers are case sensitive.
(Suggestion: Identifier naming should "see the name and know the meaning")

关键字
[‘False’, ‘None’, ‘True’, ‘and’, ‘as’, ‘assert’, ‘async’, ‘await’, ‘break’,
‘class’, ‘continue’, ‘def’, ‘del’, ‘elif’, ‘else’, ‘except’, ‘finally’, ‘for’,
‘from’, ‘global’, ‘if’, ‘import’, ‘in’, ‘is’, ‘lambda’, ‘nonlocal’, ‘not’, ‘or’,
‘pass’, ‘raise’, ‘return’, ‘try’, ‘while’, ‘with’, ‘yield’]
标识符符合规则
if name and my_list my_list1 from#1 age 2list as True
wetyui height my_log qwe&qwe

Identifier naming method
Small camel case: addName
Large camel case: AddName

1. Input and output of Python
   Input: input("Prompt information:")
   Output: print("The output is:")
   Newline: /n
   7. Format the output Method 1: Format the print
   with a percent sign (%) string
   (“my name is %s, and my age is %d” %(name,age))
   

2. print(“my name is {}, and my age is {}”.format(age,name))
   

3. Notes
   

4. operator
   
   
   
   

If x is false, x and y return the value of x else return the computed value of y

X is true, return the value of x, otherwise it returns the computed value of y

if x is true return false if false if x is false it returns true

11. Data type
Number (number)
String (string)
List (list)
Tuple (tuple)
Set (collection)
Dictionary (dictionary)
The relationship of the six
immutable data (3): Number (number), String (string) , Tuple (tuple);
variable data (3): List (list), Dictionary (dictionary), Set (collection).