search
HomeBackend DevelopmentPython TutorialWhat knowledge do you need to master to learn the basics of Python?

1.1 Python objects

Python has many built-in object types, including numbers, strings, lists, sets, tuples, dictionaries, etc. In Python, everything is an object

pickle--In Python, if there are some objects that need to be stored persistently without losing the type and data of the object, the data needs to be serialized. After serialization, when it needs to be used, it will be restored to the original data. The serialization process becomes pickle

One of the built-in data types of Python is a list: list.

list is an ordered collection.

A list consists of a series of elements arranged in a specific order. Represented by [ ]. The data types of the elements in the

list can also be different, for example:

##>>> L = ['Apple', 123, True]

2.1 Index list

starts from 0 instead of 1. When the index exceeds the range, Python will report an IndexError error, so make sure the index does not go out of range.

If you want to get the last element, in addition to calculating the index position, you can also use -1 as the index to get the last element directly.

2.2 Modify, add and delete list elements

2.2.1 Add elements

Add with append()

2.2.2 Insert elements

Insert

insert() Specify the index and value of the new element.

##>>> classmates.insert(1, 'Jack')2.2.3 Delete elements

>>> classmates

['Michael', 'Jack', 'Bob', 'Tracy', 'Adam']

1.1. To delete del, you need to know the

index

position del ABC[0]1.2. To delete the element at the end of the list, use the pop() method.

1.3. To delete the element at the specified position, use the pop(i) method, where i is the index position.

1.4. Use the pop() method to delete elements (pop), and then use the delete value.

1.5. Delete elements according to

value

remove()2.2.4 Modify elements

To replace an element with another element, you can Directly assign the value to the corresponding index position.

classmates[1] = 'Sarah'##2.3 Organization List

Method sort() sorts the list permanently, alphabetically.

Function sorted() temporarily sorts the list.

Print the list backwards reverse().

Determine the length of the list len().

2.3.1 The list contains another list

The list element can also be another list, such as:

>>> s = ['python', 'java', ['asp', 'php'], 'scheme']

To get 'php', you can write p[1] or s[2][1], so s can be regarded as a two-dimensional array.

3.1 Traverse the entire list

Use a for loop

for a in A:Don’t miss the colon

Summary after entering

print() loop

3.2 Create a numerical list

1. Function range(), range(1,5) can only print 4 numbers and cannot Print 5

2. Use the function list() to convert range() into a list list(range(1,5))

3. ** 2 hearts represent squares

4. Perform simple statistical calculations on lists of numbers min() minimum value; max() maximum value; sum() sum

5. List parsing Create a for loop and The code for the new element is merged into one line and the new element is automatically appended:

 [value**2 for value in range(1,11)]

3.3 Using part of the list

3.3.1 Slice

For operations that often take a specified index range, it is very cumbersome to use loops. Therefore, Python provides the slice (Slice) operator to simplify the operation.

1. [ : ] The starting point of the slice starts from 0, [: 4] means 0 to 3, [-3:] means the last 3

2. [2 : ] means From the 3rd to the end

3. Even if you don’t write anything, just write [ : ] to copy a list as it is.

4. [ : : step size]; [ : : -1] reverse the characters

5. The string 'xxx' can also be regarded as a list, each element Just one character. Therefore, strings can also be sliced, but the result is still a string.

6. Number of times: str(n) == str(n)[ : :-1]

3.4 Tuple

Another ordered list is called a tuple :tuple.

Tuples are very similar to lists, but tuples cannot be modified once initialized. Python calls values ​​that cannot be modified immutable, and immutable lists are called tuples. Because tuples are immutable, the code is safer. If possible, use tuple instead of list.

3.4.1 Define tuple

1. Add elements in (), separated by commas, accessed the same as list. But the value cannot be modified. But it can be assigned a value. The numbers can be directly (1,2,3,4), and the characters need to be quoted ('a', 'b', 'c')

2. When Python displays a tuple with only one element, it also A comma will be added to prevent you from misunderstanding it as a parentheses in the sense of mathematical calculations.

 t = (1,)

3. The so-called "invariance" of tuple means that the pointer of each element of tuple will never change. That is, if it points to 'a', it cannot be changed to point to 'b'. If it points to a list, it cannot be changed to point to other objects. But the list pointed to can itself be changing! How to create a tuple whose content remains unchanged? Then it must be ensured that each element of the tuple itself cannot be changed.

3.5 Set code format

1. PEP8

2. Indent format, 4 spaces

3. Line length should not exceed 79 characters

4. Use blank lines to organize the structure

>>> len(s)

4

The above is the detailed content of What knowledge do you need to master to learn the basics of Python?. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
详细讲解Python之Seaborn(数据可视化)详细讲解Python之Seaborn(数据可视化)Apr 21, 2022 pm 06:08 PM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于Seaborn的相关问题,包括了数据可视化处理的散点图、折线图、条形图等等内容,下面一起来看一下,希望对大家有帮助。

详细了解Python进程池与进程锁详细了解Python进程池与进程锁May 10, 2022 pm 06:11 PM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于进程池与进程锁的相关问题,包括进程池的创建模块,进程池函数等等内容,下面一起来看一下,希望对大家有帮助。

Python自动化实践之筛选简历Python自动化实践之筛选简历Jun 07, 2022 pm 06:59 PM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于简历筛选的相关问题,包括了定义 ReadDoc 类用以读取 word 文件以及定义 search_word 函数用以筛选的相关内容,下面一起来看一下,希望对大家有帮助。

归纳总结Python标准库归纳总结Python标准库May 03, 2022 am 09:00 AM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于标准库总结的相关问题,下面一起来看一下,希望对大家有帮助。

分享10款高效的VSCode插件,总有一款能够惊艳到你!!分享10款高效的VSCode插件,总有一款能够惊艳到你!!Mar 09, 2021 am 10:15 AM

VS Code的确是一款非常热门、有强大用户基础的一款开发工具。本文给大家介绍一下10款高效、好用的插件,能够让原本单薄的VS Code如虎添翼,开发效率顿时提升到一个新的阶段。

Python数据类型详解之字符串、数字Python数据类型详解之字符串、数字Apr 27, 2022 pm 07:27 PM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于数据类型之字符串、数字的相关问题,下面一起来看一下,希望对大家有帮助。

python中文是什么意思python中文是什么意思Jun 24, 2019 pm 02:22 PM

pythn的中文意思是巨蟒、蟒蛇。1989年圣诞节期间,Guido van Rossum在家闲的没事干,为了跟朋友庆祝圣诞节,决定发明一种全新的脚本语言。他很喜欢一个肥皂剧叫Monty Python,所以便把这门语言叫做python。

详细介绍python的numpy模块详细介绍python的numpy模块May 19, 2022 am 11:43 AM

本篇文章给大家带来了关于Python的相关知识,其中主要介绍了关于numpy模块的相关问题,Numpy是Numerical Python extensions的缩写,字面意思是Python数值计算扩展,下面一起来看一下,希望对大家有帮助。

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

VSCode Windows 64-bit Download

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft