Backend Development
Python Tutorial
Python commonly used built-in sequence structures (lists, tuples, dictionaries) study notes
Python commonly used built-in sequence structures (lists, tuples, dictionaries) study notes
列表与元组
列表用大括号[]表示，元组用圆括号（）表示。
列表可以修改，字符串与元组不可修改。
元组的分片还是元组，列表的分片还是列表。
1.列表方法：
name=["zhang3","li4","wang5"]
name.append("gou6") #添加项
name.remove("gou6") #移除第一个匹配项，也可用del name[3]来移除
name.insert(3,"gou6") #插入项
name.index("gou6") #找出第一个匹配项的位置
name.extend(["gou6","xuan7"]) #扩展
name.pop(0) #返回列表的第一项值并从列表中删除之
2.列表函数：
>>> a=list("hi guys") #把字符串转换为列表
>>> print a
['h', 'i', ' ', 'g', 'u', 'y', 's']
>>> ''.join(a) #把列表还原成字符串
'hi guys'
>>> max(a) #取得列表的最大元素
'y'
>>> len(a) #取得列表长度
7
>>> min(a) #取得最小元素
' '
>>> tuple(a) #将列表转换为元组
('h', 'i', ' ', 'g', 'u', 'y', 's')
>>> sorted(a) #将列表元素排序
[' ', 'g', 'h', 'i', 's', 'u', 'y']
3.列表遍历：
A，使用for语句遍历
for each_item in name: print(each_item)
B，使用while语句遍历
i=0 while i < len(name): print(name[i]) i += 1
4.成员资格1：
>>> sub="hello, you are a bear"
>>> "bear" in sub
True
>>> "y" in sub
True
>>> raw_input("what's your name?") in sub
what's your name?bear
True
5.成员资格2：
database=[
["zhang3","0111"],
["li4","0112"],
["wang5","0113"]
]
username=raw_input("what's your user name?")
id=raw_input("what's your id?")
if [username,id] in database: print "access granted"
6.找出10以内的整数
s = [x for x in range(0, 10) if x % 2 == 0]
7.生成九九乘法表
s = [(x, y, x*y) for x in range(1, 10) for y in range(1,10) if x>=y]
字符串
1.获取字符串
name=raw_input("what's your name?")
print "Hello," + name + ".welcome to us"
注意：Pyhton3.x版本取消了raw_input，统一使用input
输出值：
print name + repr(x) #str用于把值转换为合理的字符串，repr创建一个字符串，返回值的字符串形式 #str是一种类型（和int一样），repr是函数
2.换行符用\n表示
原始字符串，以字符串前加一个r即可，如
print r"c:\nowindows\no" path="c:\nowindows\no"; print repr(path)
3.Unicode字符串
print u"redhat"
注意：Pyhton3.x版本所有字符串都是unicode字符串
定义字符串时，双引号和单引号都是可以用的，只不过用单引号的时候可以在字符串里面使用双引号
布尔值：
>>> bool('i love you')
True
>>> bool(42)
True
>>> bool(1)
True
>>> bool('0')
True
>>> bool(0)
False
>>> bool('')
False
4.字符串方法
>>> tag="<a href=http://www.baidu.com>baidu indexpage</a>"
>>> print tag[8:28] #字符串分片
http://www.baidu.com
>>> print tag[29:-4] #字符串分片
baidu indexpage
>>> tag.replace("www.baidu.com","home.sina.com") #字符串替换
'<a href=http://home.sina.com>baidu indexpage</a>'
>>> dirs=["","usr","bin","env"]
>>> "/".join(dirs) #将列表拼接成字符串
'/usr/bin/env'
>>> print ("C:" + "\\".join(dirs))
C:\usr\bin\env
>>> path="/usr/bin/env"
>>> path.split("/") #将字符串分割成列表
['', 'usr', 'bin', 'env']
5.其它字符串方法
>>> s=' I Love you! '
>>> s.lower() #转换字符串的小写
' i love you! '
>>> s.upper() #转换字符串的大写
' I LOVE YOU! '
>>> s.title() #换换字符串为标题（所有单词首字母大写）
' I Love You! '
>>> s.islower() #判断字符串是否为小写（也可判断大写和标题）
False
>>> s.strip() #去除首尾空格，lstrip去除左边空格，rstrip去除右边空格
'I Love you!'
>>> word=s.split() #分割
>>> word
['I', 'Love', 'you!']
>>> '::'.join(word) #合并
'I::Love::you!'
>>> s.count('o') #统计出现次数
2
>>> s.find('you') #查找位置，如果找不到，则返回-1
9
>>> s.startswith('python')
False
>>> s.replace('you','yours')
' I Love yours! '
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1659
14
1415
52
1310
25
1258
29
1232
24
PHP and Python: Different Paradigms Explained
Apr 18, 2025 am 12:26 AM
PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.
Choosing Between PHP and Python: A Guide
Apr 18, 2025 am 12:24 AM
PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.
PHP and Python: A Deep Dive into Their History
Apr 18, 2025 am 12:25 AM
PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.
Python vs. JavaScript: The Learning Curve and Ease of Use
Apr 16, 2025 am 12:12 AM
Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.
How to run sublime code python
Apr 16, 2025 am 08:48 AM
To run Python code in Sublime Text, you need to install the Python plug-in first, then create a .py file and write the code, and finally press Ctrl B to run the code, and the output will be displayed in the console.
Where to write code in vscode
Apr 15, 2025 pm 09:54 PM
Writing code in Visual Studio Code (VSCode) is simple and easy to use. Just install VSCode, create a project, select a language, create a file, write code, save and run it. The advantages of VSCode include cross-platform, free and open source, powerful features, rich extensions, and lightweight and fast.
Can visual studio code be used in python
Apr 15, 2025 pm 08:18 PM
VS Code can be used to write Python and provides many features that make it an ideal tool for developing Python applications. It allows users to: install Python extensions to get functions such as code completion, syntax highlighting, and debugging. Use the debugger to track code step by step, find and fix errors. Integrate Git for version control. Use code formatting tools to maintain code consistency. Use the Linting tool to spot potential problems ahead of time.
How to run python with notepad
Apr 16, 2025 pm 07:33 PM
Running Python code in Notepad requires the Python executable and NppExec plug-in to be installed. After installing Python and adding PATH to it, configure the command "python" and the parameter "{CURRENT_DIRECTORY}{FILE_NAME}" in the NppExec plug-in to run Python code in Notepad through the shortcut key "F6".
