Python编程基础一

谁践踏了优雅 2021-10-18 10:46 324阅读 0赞

*  [Python编程基础][Python]
    
     *  [Python基础语法格式,表达式与声明][Python 1]
        
         *  [Python解释器简介][Python 2]
         *  [Python基础语法格式][Python 3]
            
             *  [注释][Link 1]
                
                 *  [行与缩进][Link 2]
         *  [关键字，标识符，标准操作符][Link 3]
            
             *  [关键字][Link 4]
                
                 *  [合法标识符][Link 5]
                 *  [引用的建立与解除][Link 6]
             *  [标准操作符][Link 7]
                
                 *  [标准数据类型][Link 8]
             *  [Python内置电池简介][Python 4]
                
                 *   *  [Python中三种赋值方式][Python 5]

# Python编程基础 #

## Python基础语法格式,表达式与声明 ##

### Python解释器简介 ###

解释器是一种让其他程序运行起来的程序，Python解释器将读取程序，并按照其中的命令执行，得出结果，实际上，解释器是代码与机器的计算机硬件之间的软件逻辑层

### Python基础语法格式 ###

注释

单行注释：#  快捷键： ctrl +/ 
    多行注释: 选中多行 ctrl+/ '''

行与缩进

Python中使用 :+空格 代表代码块

if True:
        print ("True")
    else:
        print ("False")

*  声明： 变量的创建和赋值
 *  表达式：具有返回结果的
 *  exec: 执行声明语句
 *  eval: 执行表达式

### 关键字，标识符，标准操作符 ###

关键字

显示Python中所有关键字
    import keyword
    print(keyword.kwlist)

![522E86C6403949D190717531F0AC6F96?ynotemdtimestamp=1565512382351][522E86C6403949D190717531F0AC6F96_ynotemdtimestamp_1565512382351]![uploading.gif][]转存失败重新上传取消![image][522E86C6403949D190717531F0AC6F96_ynotemdtimestamp_1565512382351]

合法标识符

*  数字，下划线，字母构成
 *  不能使用关键字
 *  不能数字开头
 *  避开内置电池中的函数

> 使用驼峰命名法，常量大写+下划线 , 变量见名知意

引用的建立与解除

a=123
    del a

标准操作符

算术运算符:
    //: 取商
    % : 取余
    **: 平方
    比较运算：
    == : 判断是否相同
    != : 判断不同
    >= <= 
    
    成员运算符
    in : 判断是否在里面
    not in: 判断是否不再里面
    
    赋值
    多重赋值: a=b=100
    多元赋值：a,b,c=100,200,300
    交换赋值： a,b=b,a

标准数据类型

*  Number 数字
 *  String 字符串
 *  List 列表
 *  Tuple 元祖
 *  Set 集合
 *  Dictionary 字典

Python3的六个标准标准数据类型中:

*  不可变数据3个： Number,String, Tuple
 *  可变数据：List Dictionary， Set

Python内置电池简介

> 所谓Python内置电池就是Python标准库中的模块

#类型
    type(obj) : 查看一个obj的类型
    isinstance(obj, cls): 查看obj是不是cls的instance
    issubclass(subclas, supcls): 查看subcls是不是supcls的子类
    
    #类型转换
    chr(i) 把一个ASCII数值,变成字符    
    ord(i) 把一个字符或者unicode字符,变成ASCII数值    
    oct(x) 把整数x变成八进制表示的字符串    
    hex(x) 把整数x变成十六进制表示的字符串    
    str(obj) 得到obj的字符串描述    
    list(seq) 把一个sequence转换成一个list    
    tuple(seq) 把一个sequence转换成一个tuple    
    dict(),dict(list) 转换成一个dictionary    
    int(x) 转换成一个integer    
    long(x) 转换成一个long interger    
    float(x) 转换成一个浮点数    
    complex(x) 转换成复数

Python中三种赋值方式

> =, shallow copy , Deep copy

import copy
    b=a # 进行赋值
    c=copy.copy(a) # 保持引用
    d=copy.deepcopy(a) # 深拷贝

[Python]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#python%E7%BC%96%E7%A8%8B%E5%9F%BA%E7%A1%80
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[Python 2]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#python%E8%A7%A3%E9%87%8A%E5%99%A8%E7%AE%80%E4%BB%8B
[Python 3]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#python%E5%9F%BA%E7%A1%80%E8%AF%AD%E6%B3%95%E6%A0%BC%E5%BC%8F
[Link 1]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E6%B3%A8%E9%87%8A
[Link 2]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E8%A1%8C%E4%B8%8E%E7%BC%A9%E8%BF%9B
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[Link 5]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E5%90%88%E6%B3%95%E6%A0%87%E8%AF%86%E7%AC%A6
[Link 6]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E5%BC%95%E7%94%A8%E7%9A%84%E5%BB%BA%E7%AB%8B%E4%B8%8E%E8%A7%A3%E9%99%A4
[Link 7]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E6%A0%87%E5%87%86%E6%93%8D%E4%BD%9C%E7%AC%A6
[Link 8]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#%E6%A0%87%E5%87%86%E6%95%B0%E6%8D%AE%E7%B1%BB%E5%9E%8B
[Python 4]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#python%E5%86%85%E7%BD%AE%E7%94%B5%E6%B1%A0%E7%AE%80%E4%BB%8B
[Python 5]: https://note.youdao.com/md/preview.html?file=%2Fyws%2Fapi%2Fpersonal%2Ffile%2F38E98AA0D39245CFB42C1AB7E444BE78%3Fmethod%3Ddownload%26read%3Dtrue%26shareKey%3D9de09f7f223ad3946b75a596f61495bc#python%E4%B8%AD%E4%B8%89%E7%A7%8D%E8%B5%8B%E5%80%BC%E6%96%B9%E5%BC%8F
[522E86C6403949D190717531F0AC6F96_ynotemdtimestamp_1565512382351]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9ub3RlLnlvdWRhby5jb20veXdzL3B1YmxpYy9yZXNvdXJjZS85ZGUwOWY3ZjIyM2FkMzk0NmI3NWE1OTZmNjE0OTViYy81MjJFODZDNjQwMzk0OUQxOTA3MTc1MzFGMEFDNkY5Nj95bm90ZW1kdGltZXN0YW1wPTE1NjU1MTIzODIzNTE
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