Note
In python, comments are divided into single-line comments and multiline comments:
Single-line comments begin with the # symbol
E.g:
# This is a comment
print('hello world')
Multi-line comments with three single quotes' '' or three double quotation marks "" "enclose the annotation content
E.g:
'''
This is a multi-line comments
This is a multi-line comments
This is a multi-line comments
'''
"""
This is a multi-line comments
This is a multi-line comments
"""
Basic data types
A digital type
1, int int
Role: Record age, grade, number
Example: age = 18
2, float type
Role: payroll records, height, weight
Example: height = 1.80
Second, the string
Action: state record described properties
Definition: single quotes, double quotes, triple quotes a series of characters contained
Example: name = 'tom'
Third, the list
Action: isoforms in accordance with the value of the attribute (the value corresponding to the index, the index starts from 0 and is representative of the position), and can be taken a certain position specified by the plurality of location history
Definition: a plurality of spaced values of any type comma within []
Example: list = [ 'bob', 18]
Fourth, Dictionary
Action: recording a plurality of different values of attributes
Is defined: {} in the plurality of elements separated by a comma, and every element by key value composed of, our value is the value stored, may be any type, is a key functional descriptive value, typically type str
例：dic={'name':'alx','age':18}
V. Boolean type bool: True, False
Role: Analyzing
Stressed: all values are built boolean value, where 0, none, empty Boolean value is False, others are True
Operators
First, arithmetic operators
+ - * / //
Second, comparison operators
> == != >=
Third, the assignment operator
1, the incremental assignment: age + = 1
2, the cross assignment: x, y = y, x
3, the chain assignment: x = y = z = 10
4, extract assignment: x, y, z = list, the right and left of the variable name values are included in one correspondence
Fourth, the logical operators
and: logic and for connecting the left and right conditions, conditions are about two to true, the final result is true
or: logic or, for connecting the left and right two conditions, as long as there is about a two conditions is True, the final result is True
not: negation
Fifth, the identity of the operator
==: determining whether the value is equal to
is: determining whether the same id
Equal to the id, the same constant value
Equal value, id not necessarily the same