Python初学汇总杂记

一时失言乱红尘 2022-12-03 08:41 191阅读 0赞

### 1,Anaconda详细安装及使用教程（带图文） ###

[https://blog.csdn.net/ITLearnHall/article/details/81708148][https_blog.csdn.net_ITLearnHall_article_details_81708148]

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**Anaconda3安装好后python不是内部或外部命令的问题解决方案:**

我的电脑-->属性-->高级系统设置-->环境变量-->系统变量-->新建path,值为:

C:\\ProgramData\\Anaconda3\\Scripts;C:\\ProgramData\\Anaconda3;C:\\ProgramData\\Anaconda3\\Library\\bin;

注意path变量 **值 **不可以有引号,如"C:\\ProgramData\\Anaconda3\\Scripts"这样是不可以的.点击"编辑文本"可避免引号.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2tpbmc1MjExMzE0MTMxNA_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2tpbmc1MjExMzE0MTMxNA_size_16_color_FFFFFF_t_70 1][]

![20200902150747145.png][]

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### 2,Python为什么要使用虚拟环境-Python虚拟环境的安装和配置 ###

[https://blog.csdn.net/godot06/article/details/81079064][https_blog.csdn.net_godot06_article_details_81079064]

### 3,Python 3 教程 ###

[https://www.runoob.com/python3/python3-tutorial.html][https_www.runoob.com_python3_python3-tutorial.html]

### 4,python学习之——import sys模块 ###

[https://blog.csdn.net/u013203733/article/details/72540075][https_blog.csdn.net_u013203733_article_details_72540075]

### 5,Python 中的 if \_\_name\_\_ == '\_\_main\_\_' 该如何理解 ###

[https://blog.konghy.cn/2017/04/24/python-entry-program/][https_blog.konghy.cn_2017_04_24_python-entry-program]

https://www.zhihu.com/question/49136398/answer/208021240

https://www.zhihu.com/question/49136398/answer/613131588

python编程中的if \_\_name\_\_ == 'main': 的作用和原理 [http://www.dengfeilong.com/post/60.html][http_www.dengfeilong.com_post_60.html]

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*  在Python中，一个***.py***文件就是一个模块，**一般情况下**，模块的名字就是**文件名**(不包括扩展名***.py***)。
 *  全局变量*\_\_name\_\_*存放的就是模块的名字。而**特殊情况**就是，当一个模块(即该.py)直接作为脚本执行时或者在交互式环境中，如Ipython、Python自带的shell等直接运行代码，\_*\_name\_\_*的值不再是模块名，而是*\_\_main\_\_*。*\_\_main\_\_*是顶层代码执行作用域的名字。
 *  通过*\_\_name\_\_*的值，我们可以判断出该模块是作为脚本正在执行还是被其他模块导入，而根据这个判断，我们就可以**选择性地执行代码**。
 *  **如果if \_\_name\_\_ == '\_\_main\_\_' 为真，就说明我们是在直接执行这个模块,这个模块的*\_\_name\_\_*的值就是\_\_main\_\_，那么所有if \_\_name\_\_ == '\_\_main\_\_' : 后面对应的缩进语句块的操作都要运行一遍；但如果为假，就说明我们是引用了这个模块，只有在需要用到它的函数时，才会被调用执行。**
 *  **直观理解：**

1.  对于当前运行的程序test.py而言，\_\_name\_\_ 变量的值是"\_\_main\_\_"。
2.  如果run.py调用了test.py，即import test，那么对test.py而言\_\_name\_\_变量的值是"\_\_test\_\_"，对于run.py而言\_\_name\_\_变量的值是"\_\_main\_\_"。
3.  有时我们写了可以直接被执行的模块（.py文件），但是在另一个程序中调用它时，我们其实只是想用一用里面写好的函数，而不是全都执行一遍。那么我们就可以把执行的部分放到if \_\_name\_\_ == '\_\_main\_\_' 中进行判断。

#test2.py中的内容
    def  test1():
        print("test2.py被调用")
    
    print ("I'm the first.")
    print (__name__)
    
    if __name__=="__main__":
         print ("I'm the second.")
    #==================================
    '''
    输出:
    I'm the first.
    __main__
    I'm the second.
    '''
    
    #import_test.py中的内容
    #######################################################
    
    #from test2 import test1
    import test2
    test2.test1(1)
    #==================================
    '''
    输出:
    I'm the first.
    test2
    test2.py被调用
    '''

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### 6,Python数据分析与展示-中国大学MOOC ###

[http://www.icourse163.org/course/BIT-1001870002][http_www.icourse163.org_course_BIT-1001870002]

### 7,Python 查看数据类型与格式 ###

[https://blog.csdn.net/Arwen\_H/article/details/83473177][https_blog.csdn.net_Arwen_H_article_details_83473177]

### 8,python -c 执行单行命令/脚本，有点意思 ###

[https://blog.csdn.net/phoenix339/article/details/90405610][https_blog.csdn.net_phoenix339_article_details_90405610]

### 9,Python3自定义包的使用及import A.b与from A import b的区别 ###

[https://blog.csdn.net/weixin\_46318945/article/details/107214447][https_blog.csdn.net_weixin_46318945_article_details_107214447]

### 10,\[Python\]自定义包及3种包导入方式 ###

[https://blog.csdn.net/humanking7/article/details/88368950][https_blog.csdn.net_humanking7_article_details_88368950]

### 11,python字符串前缀u，b，r，f用法 ###

[https://blog.csdn.net/weixin\_44662563/article/details/104357412][https_blog.csdn.net_weixin_44662563_article_details_104357412]

[https://blog.csdn.net/qq\_16234613/article/details/79448203][https_blog.csdn.net_qq_16234613_article_details_79448203]

[https://blog.csdn.net/weixin\_41010198/article/details/89354971][https_blog.csdn.net_weixin_41010198_article_details_89354971]

In [19]: print(r"name:\n赵四")
    name:\n赵四
    
    In [20]: print(r'name:\n赵四')
    name:\n赵四
    
    In [21]: r'input\n'
    Out[21]: 'input\\n'
    
    #由花括号{}包围的是替换区域。替换字段是表达式，在运行时进行评估，然后使用format()协议进行格式化。
    name = '赵四'
    age = 44
    print(f'name:{name}\nage:{age}')
    ********************************************
    运行结果：
    name:赵四
    age:44
    
    # 将包含parent包的路径添加进系统路径
    sys.path.append(r"D:\Code_Sources\Python\Test")

### 12,python中的\_\_init\_\_.py文件和导包总结 ###

[https://blog.csdn.net/weixin\_34184158/article/details/88657357][https_blog.csdn.net_weixin_34184158_article_details_88657357]

理解python中\_\_init\_\_.py和\_\_all\_\_ [https://blog.csdn.net/qq\_18824345/article/details/104879246][https_blog.csdn.net_qq_18824345_article_details_104879246]

\_\_all\_\_变量的使用  [https://blog.csdn.net/qq\_32166627/article/details/59481503][https_blog.csdn.net_qq_32166627_article_details_59481503]

Python 中 \_\_all\_\_ 的作用 [https://blog.csdn.net/orangleliu/article/details/49848413][https_blog.csdn.net_orangleliu_article_details_49848413]

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python如何将某个文件夹变成包？在那个文件夹下增加一个`__init__.py`的文件就可以把它变成一个可以被导入的包.

\_\_all\_\_ 定义了当你使用 `from <module> import *` 导入某个模块的时候所被允许导入的所有符号（这里代表变量，函数，类等）。

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### 13,Python创建包，导入包（入门必读）-示例教程 ###

[http://c.biancheng.net/view/4669.html][http_c.biancheng.net_view_4669.html]

### 14,python numpy.zeros()函数的用法 ###

[https://blog.csdn.net/lens\_\_\_/article/details/83927880][https_blog.csdn.net_lens_article_details_83927880]

[https://blog.csdn.net/qq\_39072607/article/details/89321495][https_blog.csdn.net_qq_39072607_article_details_89321495]

### 15,Python数据结构：序列（列表\[\]、元组()）与映射（字典\{\}）语法总结 ###

[https://blog.csdn.net/qq\_43744752/article/details/88928690][https_blog.csdn.net_qq_43744752_article_details_88928690]

[https://www.cnblogs.com/deepleo/p/python-list-tuple-dict.html][https_www.cnblogs.com_deepleo_p_python-list-tuple-dict.html]

### 16,python中函数的基础用法 ###

[https://cloud.tencent.com/developer/article/1627092][https_cloud.tencent.com_developer_article_1627092]

### 17,python日期和时间的操作方法汇总 ###

[https://cloud.tencent.com/developer/article/1632231][https_cloud.tencent.com_developer_article_1632231]

### 18,python中的文件读写 ###

[https://cloud.tencent.com/developer/article/1626573][https_cloud.tencent.com_developer_article_1626573]

python 读写文件以及 with open（） as的使用 [https://blog.csdn.net/xrinosvip/article/details/82019844][https_blog.csdn.net_xrinosvip_article_details_82019844]

### 19,python中yield的用法详解——最简单，最清晰的解释 ###

[https://blog.csdn.net/mieleizhi0522/article/details/82142856/][https_blog.csdn.net_mieleizhi0522_article_details_82142856]

python中的生成器和迭代器[https://cloud.tencent.com/developer/article/1634594][https_cloud.tencent.com_developer_article_1634594]

### 20,python 中if-else的多种简洁的写法 ###

[https://www.cnblogs.com/xiexiaoxiao/p/7772441.html][https_www.cnblogs.com_xiexiaoxiao_p_7772441.html]

#第1种:就是普通写法
    a, b, c = 1, 2, 3
    if a>b:
        c = a
    else:
        c = b
    
    #第二种：一行表达式,为真时放if前
    c = a if a>b else b
    
    #第三种：二维列表，利用大小判断的0，1当作索引
    c= [b, a][a > b]
    
    #第四种：传说中的黑客，利用逻辑运算符进行操作，都是最简单的东西，却发挥无限能量啊
    c = (a>b and [a] or [b])[0]
    # 改编版
    c = (a>b and a or b)
    '''
    第四种最有意思了:
    利用and 的特点，若and前位置为假则直接判断为假。
    利用 or的特点，若or前位置为真则判断为真
    '''
    # 从前往后找，and找假，or找真
    # 前真返后，
    print(111 and 222)  # 222
    # 前假返前
    print(0 and 333)  #0
    
    # 若x真【x】, x假,y真【y】，xy假【y】,只有前真返回前
    print(111 or 222) #111
    print(0 or 222) #222
    print('' or 0) # 0
    '''
    对于c = (a>b and a or b)而言，
    若（a>b and a）
    　　真：a >b and a,
    　　　　则a > b 为真
    　　假：b，
    　　　　则 a> b为假
    '''
    
    #补充：对于and的理解
    id_ = '12345'
    # 判断长度为5或者为8
    if len(id_) == 5 or len(id_) == 8:
        print(id_, '------')
    # 相反的表达为非5且非8
    if len(id_) != 5 and len(id_) != 8:
        print(id_, '+++++++')

### 21,认识python中的inf和nan ###

[https://www.jianshu.com/p/d9caa4ab46e1][https_www.jianshu.com_p_d9caa4ab46e1]

### 22,python中的异常捕获try except else finally ###

[https://cloud.tencent.com/developer/article/1634601][https_cloud.tencent.com_developer_article_1634601]

### 23,numpy中数组操作的相关函数, 常用的数学运算和统计函数汇总 ###

[https://cloud.tencent.com/developer/article/1646284][https_cloud.tencent.com_developer_article_1646284]

[https://cloud.tencent.com/developer/article/1646282][https_cloud.tencent.com_developer_article_1646282]

### 24,numpy中生成随机数的技巧汇总 ###

[https://cloud.tencent.com/developer/article/1646286][https_cloud.tencent.com_developer_article_1646286]

> `numpy.random.``randint`(*low*, *high=None*, *size=None*, *dtype=int*)  
> 
> size指定生成的元素组成的形状
> 
> X = np.random.randint(0, 5, (3, 2, 2)) 生成3x2x2的数组

### 25,py文件和ipynb文件互转 ###

把.ipynb文件转化为.py文件[https://blog.csdn.net/u013925378/article/details/83313106][https_blog.csdn.net_u013925378_article_details_83313106]

py文件和ipynb文件互转[https://blog.csdn.net/u010986753/article/details/96532965][https_blog.csdn.net_u010986753_article_details_96532965]

> **1,把.ipynb文件转化为.py文件**
> 
> 在.ipynb 文件所在的目录下按住shift打开一个终端，然后输入：  
>   
> jupyter nbconvert --to script  \*.ipynb   
>   
> 就能把当前文件夹下面的所有的.ipynb文件转化为.py文件。
> 
> **2,jupyter notebook 加载py文件(即转为ipynb文件)**
> 
> In \[ \]:%run lhr.py
> 
> 　　　加载了lhr.py文件，相当于导包。
> 
> In \[ \]:%load lhr.py
> 
> 　　　把lhr.py的代码显示出来。

## ##

[https_blog.csdn.net_ITLearnHall_article_details_81708148]: https://blog.csdn.net/ITLearnHall/article/details/81708148
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2tpbmc1MjExMzE0MTMxNA_size_16_color_FFFFFF_t_70 1]: /images/20221123/64ed50d99bd340ab9b5a5d6cc26d25e5.png
[20200902150747145.png]: /images/20221123/3822fe94f2ea485a8c2e853e2eedf976.png
[https_blog.csdn.net_godot06_article_details_81079064]: https://blog.csdn.net/godot06/article/details/81079064
[https_www.runoob.com_python3_python3-tutorial.html]: https://www.runoob.com/python3/python3-tutorial.html
[https_blog.csdn.net_u013203733_article_details_72540075]: https://blog.csdn.net/u013203733/article/details/72540075
[https_blog.konghy.cn_2017_04_24_python-entry-program]: https://blog.konghy.cn/2017/04/24/python-entry-program/
[http_www.dengfeilong.com_post_60.html]: http://www.dengfeilong.com/post/60.html
[http_www.icourse163.org_course_BIT-1001870002]: http://www.icourse163.org/course/BIT-1001870002
[https_blog.csdn.net_Arwen_H_article_details_83473177]: https://blog.csdn.net/Arwen_H/article/details/83473177
[https_blog.csdn.net_phoenix339_article_details_90405610]: https://blog.csdn.net/phoenix339/article/details/90405610
[https_blog.csdn.net_weixin_46318945_article_details_107214447]: https://blog.csdn.net/weixin_46318945/article/details/107214447
[https_blog.csdn.net_humanking7_article_details_88368950]: https://blog.csdn.net/humanking7/article/details/88368950
[https_blog.csdn.net_weixin_44662563_article_details_104357412]: https://blog.csdn.net/weixin_44662563/article/details/104357412
[https_blog.csdn.net_qq_16234613_article_details_79448203]: https://blog.csdn.net/qq_16234613/article/details/79448203
[https_blog.csdn.net_weixin_41010198_article_details_89354971]: https://blog.csdn.net/weixin_41010198/article/details/89354971
[https_blog.csdn.net_weixin_34184158_article_details_88657357]: https://blog.csdn.net/weixin_34184158/article/details/88657357
[https_blog.csdn.net_qq_18824345_article_details_104879246]: https://blog.csdn.net/qq_18824345/article/details/104879246
[https_blog.csdn.net_qq_32166627_article_details_59481503]: https://blog.csdn.net/qq_32166627/article/details/59481503
[https_blog.csdn.net_orangleliu_article_details_49848413]: https://blog.csdn.net/orangleliu/article/details/49848413
[http_c.biancheng.net_view_4669.html]: http://c.biancheng.net/view/4669.html
[https_blog.csdn.net_lens_article_details_83927880]: https://blog.csdn.net/lens___/article/details/83927880
[https_blog.csdn.net_qq_39072607_article_details_89321495]: https://blog.csdn.net/qq_39072607/article/details/89321495
[https_blog.csdn.net_qq_43744752_article_details_88928690]: https://blog.csdn.net/qq_43744752/article/details/88928690
[https_www.cnblogs.com_deepleo_p_python-list-tuple-dict.html]: https://www.cnblogs.com/deepleo/p/python-list-tuple-dict.html
[https_cloud.tencent.com_developer_article_1627092]: https://cloud.tencent.com/developer/article/1627092
[https_cloud.tencent.com_developer_article_1632231]: https://cloud.tencent.com/developer/article/1632231
[https_cloud.tencent.com_developer_article_1626573]: https://cloud.tencent.com/developer/article/1626573
[https_blog.csdn.net_xrinosvip_article_details_82019844]: https://blog.csdn.net/xrinosvip/article/details/82019844
[https_blog.csdn.net_mieleizhi0522_article_details_82142856]: https://blog.csdn.net/mieleizhi0522/article/details/82142856/
[https_cloud.tencent.com_developer_article_1634594]: https://cloud.tencent.com/developer/article/1634594
[https_www.cnblogs.com_xiexiaoxiao_p_7772441.html]: https://www.cnblogs.com/xiexiaoxiao/p/7772441.html
[https_www.jianshu.com_p_d9caa4ab46e1]: https://www.jianshu.com/p/d9caa4ab46e1
[https_cloud.tencent.com_developer_article_1634601]: https://cloud.tencent.com/developer/article/1634601
[https_cloud.tencent.com_developer_article_1646284]: https://cloud.tencent.com/developer/article/1646284
[https_cloud.tencent.com_developer_article_1646282]: https://cloud.tencent.com/developer/article/1646282
[https_cloud.tencent.com_developer_article_1646286]: https://cloud.tencent.com/developer/article/1646286
[https_blog.csdn.net_u013925378_article_details_83313106]: https://blog.csdn.net/u013925378/article/details/83313106
[https_blog.csdn.net_u010986753_article_details_96532965]: https://blog.csdn.net/u010986753/article/details/96532965