python Class：面向对象高级编程 str / repr

时间：2018-07-19 22:05:24 阅读：215 评论：0 收藏：0 [点我收藏+]

标签：rip fun lib vpd pad sig shadow expr eve

其实：__str__ 与 __repr__效果一样，人们说：__str__ 是面向用户的，而__repr__是面向程序员的，轰朵你？

官网解释：

object.__repr__(self)?

Called by the repr() built-in function and by string conversions (reverse quotes) to compute the “official” string representation of an object. If at all possible, this should look like a valid Python expression that could be used to recreate an object with the same value (given an appropriate environment). If this is not possible, a string of the form <...some useful description...>should be returned. The return value must be a string object. If a class defines __repr__() but not __str__(), then __repr__() is also used when an “informal” string representation of instances of that class is required.

object.__str__(self)?

Called by the str() built-in function and by the printstatement to compute the “informal” string representation of an object. This differs from __repr__() in that it does not have to be a valid Python expression: a more convenient or concise representation may be used instead. The return value must be a string object.

看了解释，哪里说是面向用户，哪里又说面向程序员了？？？？看到加粗字了没有，看到下滑线了没有？？？这里说的是作用于所有人好嘛！！！如果非要以自己的职位来说，好吧，好像是这么一回事，真是淫秽隐晦的表达。

不说了，先小试一下：

#!/usr/bin/python
# -*- coding: utf-8 -*-

class Student(object):
     def __init__(self, name):
         self.hah = name

class Str(Student):
     def __str__(self):
       return 'Str (name: %s)' %self.hah

class Repr(Student):
def __repr__(self):
return 'Repr(name: %s)' % self.hah

s = Student('Michael')
print s.hah

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