Python基础 - 随笔分类 - Zoe233

二维矩阵转置

摘要：解析方法一： a的矩阵形态是3*3，即3行*3列， len(a[0]) 即取矩阵a的列的长度，用于转置后作为长的长度；内部再用row[col] 将矩阵的i行j列的数据放置在j行i列；解析方法二：之前一直很少去用zip和map函数，根据方法二，补充下关于zip和map两个区别于Python2时期直阅读全文

posted @ 2018-03-23 10:05 Zoe233 阅读(506) 评论(0) 推荐(0)

python 的特殊方法 __str__和__repr__

摘要：1.类的实例化返回值 1 class Foo(object): 2 def __init__(self): 3 pass 4 5 obj=Foo() 6 print(obj) 返回值：<__main__.Foo object at 0x0000000001E9AE48> 2.__str__方法： 1 阅读全文

posted @ 2017-09-27 11:55 Zoe233 阅读(383) 评论(0) 推荐(0)

16.What is pass in Python?

摘要：What is pass in Python? Pass means, no-operation Python statement, or in other words it is a place holder in compound statement, where there shold be 阅读全文

posted @ 2017-08-25 14:24 Zoe233 阅读(172) 评论(0) 推荐(0)

15.Why lambda forms in python does not have statements?

摘要：Why lambda forms in python does not have statements? A lambda form in python does not have statements as it is used to make new function object and th 阅读全文

posted @ 2017-08-25 14:23 Zoe233 阅读(152) 评论(0) 推荐(0)

14.在Python中lambda函数是什么

摘要：在Python中lambda函数是什么？ It is a single expression anoymous function often used as inline function. lambda 匿名函数表达式及定义 lambda [ arg1 [arg2, arg3, … argN] 阅读全文

posted @ 2017-08-25 13:38 Zoe233 阅读(370) 评论(0) 推荐(0)

13.Python中的命名空间是什么

摘要：Python中的命名空间是什么？ In Python，every name introduced has a place where it lives and can be hooked for. This is known as namespace. It is like a box where 阅读全文

posted @ 2017-08-25 11:09 Zoe233 阅读(356) 评论(0) 推荐(0)

12.Python提供了哪些内建类型

摘要：There are mutable and Immutable types of Pythons built in types Mutable built-in types: List Set Dictionary Immutable built-in types: String Tuple Num 阅读全文

posted @ 2017-08-25 10:25 Zoe233 阅读(346) 评论(0) 推荐(0)

11.字典和列表生成式

摘要：字典和列表生成式 There are syntax constructions to ease the creation of a Dictionary or List based on existing iterable. 可以简化基于可迭代对象创建列表或字典的语法结构。列表生成式List Co 阅读全文

posted @ 2017-08-24 14:53 Zoe233 阅读(213) 评论(0) 推荐(0)

10.如何通过值或引用传递参数

摘要：如何通过值或引用传递参数？ Everything in Python is an object and all variables hold references to the objects. The references values are according to the functions 阅读全文

posted @ 2017-08-24 14:33 Zoe233 阅读(236) 评论(0) 推荐(0)

9.列表和元组的区别

摘要：列表和元组的区别 The difference between list and tuple is that list is mutable while tuple is not. Tuple can be hashed for as a key for dictionaries. list和tup 阅读全文

posted @ 2017-08-24 13:32 Zoe233 阅读(312) 评论(0) 推荐(0)

8.Python中装饰器是什么？

摘要：Python中装饰器是什么？ A Python decorator is a specific change that we make in Python syntax to alter functions easily. Python decorator是我们在Python语法中使用的一个特定的更阅读全文

posted @ 2017-08-23 15:17 Zoe233 阅读(251) 评论(0) 推荐(0)

7.哪些工具可以帮助查找bug或进行静态分析

摘要：哪些工具可以帮助查找bug或进行静态分析？ PyChecker is a static analysis tool that detects the bugs in Python source code and warns about the style and complexity of the 阅读全文

posted @ 2017-08-23 15:09 Zoe233 阅读(273) 评论(0) 推荐(0)

6.Python中内存是如何管理的？

摘要：Python中内存是如何管理的？ Python memory is managed by Python private heap space. All Python objects and data structures are located in a private heap. The prog 阅读全文

posted @ 2017-08-23 14:56 Zoe233 阅读(714) 评论(0) 推荐(0)

5.Python是怎么解释的？

摘要：Python是怎么解释的？ Python language is an interpreted language. Python program runs directly from the source code. It converts the source code that is writt 阅读全文

posted @ 2017-08-23 13:33 Zoe233 阅读(736) 评论(0) 推荐(0)

4.pickling 和unpickling是什么？

摘要：pickling 和unpickling是什么？ Pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using dump f 阅读全文

posted @ 2017-08-22 13:44 Zoe233 阅读(724) 评论(0) 推荐(0)

3.PEP 8是什么？

摘要：PEP 8是什么？ PEP 8 is a coding convention, a set of recommendation, about how to write your Python code more readable. PEP 8是一种编码规范和建议，关于如何编写您的Python代码，使阅读全文

posted @ 2017-08-22 11:58 Zoe233 阅读(471) 评论(0) 推荐(0)

2.Python是什么？使用Python的好处是什么？

摘要：Python是什么？使用Python的好处是什么？答： Python is a programming language with objects, modules, threads, exceptions and automatic memory management. The benefits 阅读全文

posted @ 2017-08-22 11:18 Zoe233 阅读(1415) 评论(0) 推荐(0)

Redis介绍及字符串操作

摘要：一、前言不同程序之间实现通信的方法？ A.通过不同程序之间建立socket，实现通信。实际应用适用于使用broker，如RabbitMQ，ZeroMQ. B.通过Json，Pickle，利用文件的写入和读取实现不同程序之间的通信，但是效率低。 C.通过在不同的程序之间加入一个中间代理程序，中间代理阅读全文

posted @ 2017-08-22 10:42 Zoe233 阅读(200) 评论(0) 推荐(0)

字符串转换为二进制

摘要：符串如果直接全部都是utf-8编码，每个汉字有3个字节，每个英文有1个字节，1 bytes=8 bit。先将字符串通过ord()转换为ascii码，再通过bin()将其转换为二进制。阅读全文

posted @ 2017-08-22 09:55 Zoe233 阅读(2233) 评论(0) 推荐(0)

上亿在线用户维护最高效的设计思想，二进制位存储变更的应用场景

摘要：应用场景：在某大型互联网公司，有上亿的用户，要统计当前用户的在线人数和在线用户id，最快的实现方法是什么？答：一般情况下，我们都使用数据库字段在用户登陆状态发生变更时进行变更，查找在线人数和在线用户id都是用select的方式。但是这种方式在实际中，调取速度非常慢，效率比较低，时效性差。在red 阅读全文

posted @ 2017-08-21 17:10 Zoe233 阅读(483) 评论(0) 推荐(0)

随笔分类 - Python基础