Python空构造函数
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Python empty constructor
提问by Narek Tarasyan
Is there any way to create an empty constructor in python. I have a class:
有没有办法在python中创建一个空的构造函数。我有一堂课：
class Point:
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
now I initialize it like this:
现在我像这样初始化它：
p = Point(0, 5, 10)
How can I create an empty constructor and initialize it like this:
如何创建一个空的构造函数并像这样初始化它：
p = Point()
回答by Waxrat
class Point:
def __init__(self):
pass
回答by Shreyash S Sarnayak
As @jonrsharpe said in comments, you can use the default arguments.
正如@jonrsharpe 在评论中所说，您可以使用默认参数。
class Point:
def __init__(self, x=0, y=0, z=0):
self.x = x
self.y = y
self.z = z
Now you can call Point()
现在你可以打电话 Point()
回答by William Pearsall
You can achieve your desired results by constructing the class in a slightly different manner.
您可以通过以稍微不同的方式构造类来实现您想要的结果。
class Point:
def __init__(self):
pass
def setvalues(x, y, z):
self.x = x
self.y = y
self.z = z
回答by PurpleJo
You should define the __init__()method of your Pointclass with optional parameters.
您应该使用可选参数定义类的__init__()方法Point。
In your case, this should work:
在您的情况下，这应该有效：
class Point:
def __init__(self, x=0, y=0, z=0):
self.x = x
self.y = y
self.z = z
pointA = Point(0, 5, 10)
print("pointA: x={}, y={}, z={}".format(pointA.x, pointA.y, pointA.z))
# print "pointA: x=0, y=5, z=10"
pointB = Point()
print("pointB: x={}, y={}, z={}".format(pointB.x, pointB.y, pointB.z))
# print "pointB: x=0, y=0, z=0"
