Learn Python Day01

What is Python

1. Object-oriented Interpretation line language

2. A very rich library

3. Indent using tabs as statements (white space)

Advantages:

　　1. Free, open source

2. Scalability, embeddable

3. A very rich library

Disadvantages:

　　1. Slow operating Speed

2. Less Chinese information

3. Code cannot be encrypted

Simple input and output:

Input: Name=input ("Please enter your name:")

　　Output: Print ("Hello World")

　　

Formatted output symbol:

%c converted to character (ASCII value, or string of length one)

%r takes precedence over string conversions with the repr () function

%s takes precedence over string conversion with the STR () function

%d/%i turns into signed decimal numbers

%u turns into unsigned decimal number

%o Turn unsigned octal number

%x%x to unsigned hexadecimal number (x/x/represents the case of the converted hexadecimal character)

%e/%e turns into scientific notation (e/e control output)

%f/%f to floating point number (small part stage)

Shorthand for%g/%g%e and%f/%e and%f

Percent output% (the formatted string includes a percent semicolon, then must be used)

\ n line-break output

"STR" *n output n times

Print ("No newline output:", end= "")

Variable:

Cases:

Name = "a" #不需要定义类型

Naming rules:

1. Only letters, numbers, and underscores can be included. You can start with a letter underscore, but you cannot start with a number.

2. You cannot include spaces, but you can use underscores to split them

3. You cannot use a keyword in python as a variable name

4. Suggested hump naming method to increase program readability

Key words:

Data type:

Int (integer)

Number float (floating point type)

Complex (plural)

BOOL (Boolean)

String (String)

List (lists)

Tuple (Ganso)

Sets (collection)

Dictionary (dictionary)

Type () #查看类型

Comments:

#

Single-line Comment

"""    """

Multi-line comments

Action string:

Intercept string Syntax:

Variable "start subscript: End Subscript"

The plus sign (+) is the connector for the string

An asterisk (*) indicates that the current string is copied

List:

list = [' abc ', 3, ' AAA ']

The list is written between square brackets, separated by commas

can be sliced and indexed as a string

You can use the plus sign (+) for stitching

The elements in the list can be changed.

Ganso

The Ganso is written in parentheses, and the elements are separated by commas.

Tuple1 = (' abc ', 1, ' AAA ')

Attention:

A tuple cannot be changed, but it can contain mutable objects. such as list lists

A ganso that constructs 0 or 1 elements has a special syntax rule:

tuple1= () #空元祖

Tuple2= (1,) #一个元素, you need to add a comma after the element

Dictionary:

A dictionary is a type of mapping, using {}, which is an unordered key (key) value pair set

Dict1 = {}

Dict2 = {' name ': ' Amanda ', ' age ': ' 10 '}

Attention:

A dictionary is a type of mapping

The key (key) must use the immutable type (string, numeric, Ganso), and the key must be unique in the same dictionary.

Create an empty dictionary with {}

Operator:

Plus (+), minus (-), multiply (*), except (/), take rest (%), power (*), and divide the portion of the returned quotient (//)

Logical operators:

and #布尔 "and"

or #布尔 "or"

Not #布尔 "non"

Bitwise operators:

A = 60

b = 13

　　& #按位与运算符: Two values that participate in the operation, and if two corresponding bits are 1, the result of that bit is 1 a&b result 122 binary 00001100

　　| #按位或运算符: As long as the corresponding two binary has one for 1 o'clock, the result bit is 1 a|b result 612 binary 00111101

　　^ 　 #按位异或运算符: When two corresponding binary differences, the result is 1 a^b result 492 binary 00110001

　　~ #按位取反运算符: Reverse every bits of the data, turn 1 into 0, turn 0 into 1 ~a result-612 binary 11000011　　

　　<< #左移动运算符: High Drop, low 0 a<<2 result 2,402 binary 11110000

　　>> #右移动运算符: High 0, low discard a>>2 result 152 binary 111100 00

　　　　　　　　　　　

Learn Python Day01