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Outline basic computer knowledge base of ~ Python
A few days before school finished content python fundamental part of the foundation - computer, gathering information on the first outline of the knowledge base to learn today
Computer Basics of programming
What is the programming language
What is programming
Why Programming
Composed of five computer
cpu
Controller
Operator
RAM
External memory
input device
Output Device
IO device
Application process starts
Multi-core CPU
32 and 64
Mechanical hard disk works
SSD
The basic computer operating system
What is the file
What is the application procedure
The role of the operating system
The three main components of a computer system
The operating system boot process
Classification of programming languages
Machine language
Assembly language
High-level language
Interpreted language
Compiled language
Network bottleneck effect
python basis
Python implementation of the program in two ways
Interactive
Command line
variable
What is variable
Compositional variables
Naming the variable name
Both formats defined variable names
constant
What is constant
Define constants way
python variable memory management
Reference count
python garbage collection
Small integer pool
Fancy assignment
Chain assignment
Cross-type assignment
Note
Single-line comments
Multi-line comments
Basic data types
Digital Type
String type
List Type
Dictionary Type
Boolean
unzip
User interaction with python
Three ways formatted output
Placeholder
format format
f-String formatting
Basic operators
Arithmetic Operators
Comparison Operators
Logical Operators
Assignment Operators
Identity operator
Operator Precedence
determining if the flow control
Single-branch structure
Two-branch structure
Multi-branch structure
if nested
The while loop flow control
while+break
while+continue
while+else
while nesting
The for loop flow control
for+break
for+continue
for+else
for nesting
Ordered or unordered
Variable or invariable
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A data type built-in method
Summary template:
effect
Defined way
Built-in method
A plurality of stored value or values
Ordered or disordered (order: that is indexed and disorderly: no index)
Variable or non-variable (Key)
Variable: Variable value change id unchanged
Immutable: variable id variable value becomes
id constant value of the variable, i.e., modified on the basis of the original value, for the variable data type; id value becomes variable, i.e., to re-apply a new value into the space, compared with immutable data types.
1.1 numeric type built-in method
1.1.1 Integer
Role: that age, number, grade, etc.
Is defined by: may be used int (), the purely digital string to decimal integer
x = 10 x = int('10') x = int(10.1) print(x) # 10 x = int('10.1') # 报错,int()里10.1本来就是字符串了，不需要加引号 print(x)Built: There is no built-in method, only arithmetic + - * / and compare operations> <> = <=
A plurality of stored value or values: a stored value
Ordered or disordered: Integer only one value, this argument is not
Variable or non-variable: immutable
x=10 print(id(x)) # id为1925279488 x=11 print(id(x)) # id为1925279520Variable id value becomes, the int immutable
1.1.2 Float
Role: to represent salary, height, weight, etc.
It is defined by: can float () method of the string to a purely digital floating-point number
x = float('111') print(x) # 输出为111.0 print(type(x)) # <class 'float'>Built: There is no built-in method, only arithmetic + - * / and compare operations> <> = <=
A plurality of stored value or values: one
Orderly or disorderly: not this statement
Variable or non-variable (Key): immutable
Numeric types are not variable
1.2 string type built-in method
Role: description of the nature of things, such as the person's name, a single loving, address, country, etc.
Defined: Use '', '', '' '' '' "" "" "" wrapped string of characters
s = 'sdfklsdjfk' s = b'sdkfljl' # 打印出来的bytes类型,二进制类型,010101010100110100 # 有这种二进制的定义方式,其实一点用都没有 print(s) # \n 换行 s = 'a\na' # 碰到斜杠了,计算机就清楚下一个字符和\拼接在一起会有特殊的意义 print(s) # \t 缩进4个空格 s = 'a\t\ta' print(s) # 输出结果为a a # \r 回退上一个打印结果,覆盖上一个打印结果 print('\ra',end='') # print('\\ra',end='') # 加一个\让后面的\变得无意义 # s = 'a\\na' # print(s) # s = r'\ra\t\na' # raw # print(s)Built-in method:
s='nick handsome'
# 一、优先掌握：
# 1、按索引取值（只可取，不可改变）
print(s[1]) # 输出为i
# 2、切片（顾头不顾尾，步长）
# 索引切片
msg = 'hello nick'
# 0123456789 # 索引序号
print(f'切片3-最后: {msg[3:]}') # 从索引3的位置切片到最后一位，输出为lo nick
print(f'切片3-8: {msg[3:8]}') # 输出为lo ni
print(f'切片3-8，步长为2: {msg[3:8:2]}') # 输出为l i
print(f'切片3-最后，步长为2: {msg[3::2]}') # 输出为l ik
# 了解，步长为正从左到右；步长为负从右到左
print('\n**了解知识点**') # **了解知识点**
print(f'切片所有: {msg[:]}') # 切片所有: hello nick
print(f'反转所有: {msg[::-1]}') # 反转所有: kcin olleh
print(f'切片-5--2: {msg[-5:-2:1]}') # 切片-5--2: ni
print(f'切片-2--5: {msg[-2:-5:-1]}') # 切片-2--5: cin
# 3、for循环
s = 'nick handsome'
for i in s:
print(i) # 逐行打印s中的每个字符
# 4、strip() 移除空白
s1 = ' nick handsome '
print(s1.strip()) # 去两端的空白
s2 = '***!!!!!nick handsome----***'
print(s2.strip('-*!')) # 指定多个字符一起去掉,只要strip里面有的字符就全部干掉
print(s2.strip('nick')) # 指定多个字符一起去掉,只要strip里面有的字符就全部干掉
# s2.strip('*-!') # 首先判断字符串s的两端字符,为*,再去strip里找有没有*,有就去掉,再去判断字符串s的两端字符,!-,再从strip里面找,有去掉,没有停止去掉
# 5、split() 切割
s2 = '***!!!!!nick handsome----***'
print(s2.split()) # 默认以空格切割字符串
print(s2.split('!')) # 以!切割
print(s2.split('!', 2)) # 以！切割，最大切割次数为2，也就是从找到第一个！开始切割，找到第二个！切割后就结束切割
# 6、in 或 not in 返回结果就是True或False
s2 = '***!!!!!nick handsome----***'
print('*' in s2) # True
print('$' not in s2) # True
# 7. 长度len
s2 = 'nick handsome'
print(len(s2)) # 求字符串的长度
# 二、需要掌握：
# 1. lstrip() 和 rstrip() 左移除和右移除
s2 = '***!!!!!nick handsome----***'
print(s2.lstrip('*')) # !!!!!nick handsome----***
print(s2.rstrip('*')) # ***!!!!!nick handsome----
# 2. rsplit() 从右开始切割
info = 'nick:male:19'
print(f"info.rsplit(':', 1): {info.rsplit(':', 1)}") # 从右开始切割，1表示只切割一次，输出为info.rsplit(':', 1): ['nick:male', '19']
# lower&upper 把大写变小写和把小写变大写
s3 = 'aaabbJ'
print(s3.lower()) # 把字符串中所有大写变成小写，aaabbj
print(s3.upper()) # 把字符串中所有小写变成大写，AAABBJ
# startswith&endswith 以什么开头和以什么结尾，返回结果为True或False
s3 = 'aaabbJ'
print(s3.startswith('b')) # False
print(s3.endswith('J')) # True
# join(用的比较多)一般和split联用
s3 = ' '
print(s3.join(['234', '234', '234'])) # 以s3也就是以空格为间隔符,拼接列表里的每一个元素，输出为234 234 234
s = '辣条/薯片/汽水/泡面/火腿肠/枸杞/当归/鹿茸'
s1 = s.split('/') # 先把s以/切分
print(s1) # ['辣条', '薯片', '汽水', '泡面', '火腿肠', '枸杞', '当归', '鹿茸']
print('*'.join(s1)) # 再把切分后的每一个元素间用*连接
# 输出结果为:辣条*薯片*汽水*泡面*火腿肠*枸杞*当归*鹿茸
# replace 替换
s2 = 'yongjiu handsome'
print(s2.replace('yongjiu', 'gebilaowang')) # 用gebilaowang替换掉yongjiu
## isdigit(纯数字)/isalpha(纯字母) 返回结果为True或False
s2 = '12312'
print(s2.isdigit()) # True
s3 = 'aaac1c'
print(s3.isalpha()) # False
# 3、做了解即可
# find|rfind|index|rindex|count 一般常用find
s2 = '**23423***ni234234ck $$ hand223423some******'
print(s2.find('$')) # 从左找,找到第一个停止,找不到返回-1
print(s2.rfind('$')) # 从右找,找到就停止,找不到返回-1
print(s2.index('$')) # 找不到报错
print(s2.rindex('$')) # 找不到报错
- A plurality of stored value or values: one
- Ordered or disordered: orderly, as long as there is an index, are ordered, so the string is ordered
- Variable or non-variable (Key): immutable
Built-in string methods much Hutchison multi-purpose, multi-play exercises the code, in order to skillfully use