跟黄哥学python序列文章之python方法链(method chaining)

跟黄哥学python序列文章之python方法链(method chaining)

写这篇文章来由，有朋友说下面这样的代码看不懂。

choice = raw_input("please input:\n").strip()[0].lower()
不少对于有经验的程序员来讲，这些都不是事，
但对于初学者来讲，看到这样的语法头有点大。

这个实际上是面向对象中方法链的概念。

请看维基百科上Method chaining的定义

Method chaining, also known as named parameter idiom,   
	is a common syntax for invoking   multiple method calls 
	in object-oriented programming languages.
	Each method returns an   object, allowing the calls 
	to be chained together in a single statement without requiring   
	variables to store the intermediate results.
	Local variable declarations are syntactic   
	sugar because of the difficulty humans have with deeply nested method calls.
	A method chain is also known as a train wreck due to the increase 
	in the number of methods that come one after another in the same 
	line that occurs as more methods are chained together
	even though line breaks are often added between methods.

具体在python中，请看黄哥的分析：

有的python初学者对python方法连续调用不是很清楚，像雾里看花同样。
python一切都是对象，对象调用它的方法，若是带返回值，放回值也是对象，  
这个返回值也有方法，固然就能够用点号调用它的方法，   
如此下去，就是python方法链调用也。

如何设计方法链python代码

# coding:utf-8
"""
如何经过学习python学会编程
https://github.com/pythonpeixun/article/blob/master/python/how_to_learn_python.md
黄哥python远程视频培训班
https://github.com/pythonpeixun/article/blob/master/index.md
黄哥python培训试看视频播放地址
https://github.com/pythonpeixun/article/blob/master/python_shiping.md
黄哥python培训 咨询qq:1465376564
"""


class Person(object):
    """方法链小sample"""

    def name(self, value):
        self.name = value
        return self # 返回实例对象本身才能再调用实例对象的方法。

    def work(self, value):
        self.working = value
        return self

    def introduce(self):
        print "你好, 个人名字:", self.name, ",个人工做:", self.working, ",教初学者学会编程!"

person = Person()
person.name("黄哥").work("黄哥python培训").introduce()

php方法链代码

<?php
	/*
	黄哥php培训 咨询qq:1465376564
	https://github.com/pythonpeixun/article/blob/master/php_education.md
	*/


	class Person{
	    public $name;
	    public $working;

	    public function setName($value){
	        $this->name = $value;
	        return $this;
	    }

	    public function work($value){
	        $this->working = $value;
	        return $this;
	    }

	    public function introduce(){
	        echo "你好, 个人名字:".$this->name.",个人工做:".$this->working.",教初学者学会编程!\n";
	    }
	}

	$person = new Person();
	$person->setName("黄哥")->work("黄哥php培训")->introduce();

点击黄哥python培训试看视频播放地址

黄哥python远程视频培训班