Python Basics (9): Supplemental

1. Class ():

Automatically call internal method __init__ ()

int (), str (), list (), bool (), tuple (), Dict (), object-oriented class.

2. Int:

　　A. Method of Creation (two):

1). A = 123

2). A = in (123)

__init__ (self, x, base=10): x: Number. Base: The default is 10 binary.

B. Additions:

python internal optimization: A duplicate default memory address within the range ( -5< contains > ~257< does not include >)

　　　　View memory address: ID (variable name)

　　　　view string, array length:len (string, array)

C. Length limitation:

int type:

32-bit system: integer with 32 bits, value range: -2**31~2**31-1 ( -2147483648~2147483647)

64-bit system: integer with 64 bits, value range: -2**63~2**63-1 ( -9223372036854775808~9223372036854775807)

Automatically converted to a long type after it is exceeded.

Long type:

No length limit, determined by memory size.

bytes

3. STR:

A. String creation (two ways):

S1 = "Alex"

S1 = str ("Alex")

__init___ (Self, value= ", Encoding=none, errors= ' strict '): Value: The content parameter of the string. Encoding: Encoding defaults to none. Errors: The default is strict mode (strict), which is not changed by default.

No arguments: Creates an empty string.

1 Parameters: Create a normal string

2 parameters: Int (bytes, encoded)

B. Specific methods:

Strip (): Go to both ends of the space.

Lstrip (): left blank.

Rstrip (): Go to the right space.

StartsWith (): Start with XXX.

EndsWith (): End With XXX.

Find (): Finds a subsequence (can be one character or more than one character).

Replace (): Replaces a subsequence in a string with the specified value.

Upper (): variable capitalization.

Lower (): lowercase.

Isalnum (): Whether it is a letter or a number.

Isalpha (): Whether it is a letter or not.

IsDigit (): Determines whether it is a number.

Islower (): Determines whether it is lowercase.

Isspace (): Determines whether it is a space.

Istitle (): Determines whether it is a title.

Isupper (): Determines whether it is uppercase.

C. Public methods:

Index: [0],[1] ... Only one element can be taken

Slice: [0:1],[0:2] ... Multiple elements are preferable

Coding:

Len ():

For

Python Basics (9): Supplemental