我必须写四个类：平行四边形，矩形，菱形和方形。 init方法的参数应始终按以下顺序输入:( base，side，theta），而不是每个类'init都将采用所有三个。因此，例如，Rectangle将只采用（base，side）。这些类的对象必须具有以下方法：area（） - 返回形状的区域平行四边形的区域由基本侧sin（theta）计算。看看math.radians函数在度和弧度之间进行转换。 bst（） - 返回三个燕麦的列表：[base，side，theta]。即使一个形状不需要其输入的参数之一，它仍然应该能够返回它。 （例如，10×10平方将返回：[10,10,90]）。打印时，每个形状都应返回一个带有文本的字符串，格式如下\我是一个面积为“的形状。”四个例子，一个10 x 10的正方形将返回字符串：\我是一个面积为100的正方形“。这就是我到目前为止所拥有的 http://pastebin.com/CkGndsRU
答案 0 :(得分：0)
当每个类的某些组件相同时，继承很有用，因此您可以将它们包含在父类中，而无需在每个类中再次重写它们。看一下你的代码，关于类的唯一相同的东西是基本实例属性，所以你可以将很多东西放到父类中。
这是继承的一个例子，虽然它类似
class square:
def __init__(self, sidelen):
self.sidelen = sidelen
def area(self):
return self.sidelen**2
class cube(square):
def area(self):
return self.sidelen**3
这里，cube类从square类继承它的init方法，但是会覆盖它的area方法。
答案 1 :(得分：0)
以下是您的代码中用于演示class and inheritance：
的工作示例<?php
$username='someUser'
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Load From PHP</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
<script>
var username = encodeURI( <?php echo isset($username) ? "'".$username."'" : ''; ?> );
$(function(){
var url='load.php?username='+username;
// load once after 2 seconds
setTimeout(function(){ $.get(url, function(response){ $('#load_msgs').html(response); } ); }, 2000);
// load every 2 seconds
setInterval(function(){ $.get(url, function(response){ $('#load_msgs_repeat').append(response+'<br>'); } ); }, 2000);
});
</script>
</head>
<body>
<h4>Div loaded once</h4>
<div id="load_msgs"></div>
<br>
<h4>Div loaded every 2 seconds</h4>
<div id="load_msgs_repeat"></div>
</body>
</html>
注意：我在上面的例子中使用Python2.7
答案 2 :(得分：0)
没有必要用参数调用super ...这是继承的另一个例子 - 形状......
编辑：我讨厌这个网站如何将python代码转换为使用空格而不是标签...这是一种恶心的习惯，可以极快地增加文件大小......
我在这个线程（区域函数和tostring方法）中添加了一些基于另一个例子的例子
# --
# -- Basic example of classes and inheritance by using an easy to follow idea - shapes - and extending them.. - Josh 'Acecool' Moser
# --
# --
# -- Shape Base-Class - This only holds the name of the object and nothing else...
# --
class Shape:
# -- Class Vars
name = "Shape"
# --
# -- The ToString function for this class - it is what is called when you print( str( shape ) )
# -- Note: You need to use str( x ) to convert that object to a string - most data-types have an appropriate To-String function to do this and if not you'll be left with something like <address / reference / other info>
# --
def __str__( self ):
return "I am a " + self.name + " defined as " + type( self ).__name__ + "( ... )"
# --
# -- Square extends Shape - A Square has the same width / height so we only need 1 value, we'll use X but it can be anything we want..
# --
class Square( Shape ):
# -- Class Vars
name = "Square"
# -- Set x to a default value
x = 0
# --
# -- Object Creation - We'll use this to create a square: Square( 10 ) for example.
# --
def __init__( self, _x ):
# -- Run the BaseClass - Although Shape doesn't do anything, it's here to fall all the way through just in case...
super( ).__init__( )
# -- We can set the name here, or just leave it in the class - Note: The same can be done in Rect but I omitted it to keep this example short...
# -- self.name = "Square"
# -- Update X for this instance - Note: I'd typically use a Getter / Setter for all variables to prevent incorrect data-types or usage
self.x = _x
# --
# -- The ToString function for this class - it is what is called when you print( str( shape ) )
# -- Note: You need to use str( x ) to convert that object to a string - most data-types have an appropriate To-String function to do this and if not you'll be left with something like <address / reference / other info>
# --
def __str__( self ):
return "I am a " + self.name + " defined as " + type( self ).__name__ + "( " + str( self.x ) + " ) ie x = " + str( self.x ) + " with an area of " + str( self.area( ) )
# --
# --
# --
def area( self ):
return self.x * self.x
# --
# -- Cube extends Shape - This cube is coded to change a few of the functions from Square - it is also coded as a 1 var shape, ie all sides are the same..
# --
class Cube( Square ):
# -- Class Vars
name = "Cube"
# --
# -- Object Creation - We'll use this to create a square: Square( 10 ) for example.
# --
def __init__( self, _x ):
# -- Run the BaseClass - Although Shape doesn't do anything, it's here to fall all the way through just in case...
super( ).__init__( _x )
# --
# -- The ToString function for this class - it is what is called when you print( str( shape ) )
# -- Note: You need to use str( x ) to convert that object to a string - most data-types have an appropriate To-String function to do this and if not you'll be left with something like <address / reference / other info>
# --
def __str__( self ):
return super( ).__str__( ) + " with an area of " + str( self.area( ) )
# --
# --
# --
def area( self ):
return self.x ** self.x
# --
# -- Rectangle extends Square extends Shape ( Same as class Rect( Square, Shape ) but Square extends Shape so it shouldn't be needed for fallthrough )
# -- A Rectangle has different width and height so we'll use x from square for width, and add y for height to make a rectangle...
# --
class Rect( Square ):
# -- Class Vars
name = "Rectangle"
# -- Set y to a default value so we don't need to worry about errors if it isn't defined
y = 0
# --
# -- Object Creation - We'll use this to create a rectangle: Rect( 10, 20 ) for example.
# --
def __init__( self, _x, _y ):
# -- Run the BaseClass - This is needed to set self.x by allowing Square to execute that - we could also do self.x = x, but this is an example of inheritance so...
super( ).__init__( _x )
# -- Update y for this instance - Note: I'd typically use a Getter / Setter for all variables to prevent incorrect data-types or usage - but to keep things short, I kept things simple...
self.y = _y
# --
# -- The ToString function for this class - it is what is called when you print( str( shape ) )
# -- Note: You need to use str( x ) to convert that object to a string - most data-types have an appropriate To-String function to do this and if not you'll be left with something like <address / reference / other info>
# --
def __str__( self ):
return "I am a " + self.name + " defined as " + type( self ).__name__ + "( " + str( self.x ) + ", " + str( self.y ) + " ) ie x = " + str( self.x ) + " / y = " + str( self.y ) + " with an area of " + str( self.area( ) )
# --
# --
# --
def area( self ):
return self.x * self.y
# --
# -- Main
# --
def main( ):
# -- Create a rectangle with x = 10, y = 20
_shape = Rect( 10, 20 )
# -- Create a rectangle with x = 30, y = 40
_shape2 = Rect( 30, 40 )
# -- Create a square with x = 50
_shape3 = Square( 50 )
# -- Create a simple Shape - with nothing attached...
_shape4 = Shape( )
# -- Create a simple Cube...
_shape5 = Cube( 4 )
# --
# -- I'm doing the output text here so you know that declaring other shapes won't overwrite other values in other objects
# -- if I were set up the output text after each object creation and allow another object to be created afterwards
# -- it wouldn't prove that the objects have their own values meaning it would be possible for the variables to be
# -- static ( shared among all types so the last object to update that value would mean all objects have that value )
# -- but, by having all text here, it shows that the variables aren't static - they're private..
# --
# -- Note: I left the original outputs commented to the right of the new str( object ) method so you could see one way of doing it vs the benefits of having a __str__ ToString method handle it for you...
# --
# Define the text output var... Then add to it for each line...
_text = ""
# -- This is calling Rect ToString function normally
# -- Originals output without using tostring method -- # _text += _shape.name + " x: " + str( _shape.x ) + " y: " + str( _shape.y ) + "\n"
_text += str( _shape ) + "\n"
# -- This is calling Square ToString function ( ie super of Rect is Square ) -- Output: I am a Rectangle defined as Rect( 10 ) ie x = 10
_text += str( super( Rect, _shape ).__str__( ) ) + "\n"
# -- This is calling Shape ToString function ( ie super of Square is Shape ) -- Output: I am a Rectangle defined as Rect( ... )
_text += str( super( Square, _shape ).__str__( ) ) + "\n"
# -- This calls Rect ToString function normally
# -- Originals output without using tostring method -- # _text += _shape2.name + " x: " + str( _shape2.x ) + " y: " + str( _shape2.y ) + "\n"
_text += str( _shape2 ) + "\n"
# -- This calls Square ToString function normally
# -- Originals output without using tostring method -- # _text += _shape3.name + " x: " + str( _shape3.x ) + "\n"
_text += str( _shape3 ) + "\n"
# -- This calls Shape ToString function normally
_text += str( _shape4 ) + "\n"
# -- This calls Shape ToString function normally
_text += str( _shape5 ) + "\n"
# -- Output:
# I am a Rectangle defined as Rect( 10, 20 ) ie x = 10 / y = 20 with an area of 200
# I am a Rectangle defined as Rect( 10 ) ie x = 10 with an area of 200
# I am a Rectangle defined as Rect( ... )
# I am a Rectangle defined as Rect( 30, 40 ) ie x = 30 / y = 40 with an area of 1200
# I am a Square defined as Square( 50 ) ie x = 50 with an area of 2500
# I am a Shape defined as Shape( ... )
# I am a Cube defined as Cube( 4 ) ie x = 4 with an area of 256 with an area of 256
return _text
# --
# -- Call main and print the return contents...
# --
print( main( ) )