新手在学习python时候,会遇到很多的坑,下面来具体说说其中一个。
在使用python编写面向对象的程序时,新手可能遇到TypeError: this constructor takes no arguments这个错误。
例如下面的程序:
class Ball:
def _init_(self,color,size,direction):
self.color=color
self.size=size
self.direction=direction
def bounce(self):
if self.direction=="down":
self.direction="up"
myBall=Ball("red","small","down")
print "I just created a ball."
print "My ball is",myBall.size
print "My ball is",myBall.color
print "My ball's direction is",myBall.direction
print "Now I'm going to bounce the ball"
print
myBall.bounce()
print "Now the ball's direction is",myBall.direction
运行会报错:
======================= RESTART: H:\python\bounce1.py =======================
Traceback (most recent call last):
File "H:\python\bounce1.py", line 11, in
myBall=Ball("red","small","down")
TypeError: this constructor takes no arguments
出错原因是,在python中构造函数书写格式是__init__,而不是_init_,即在init两侧都是双下划线,不是单下划线。
修改后如下:
class Ball:
def __init__(self,color,size,direction):
self.color=color
self.size=size
self.direction=direction
def bounce(self):
if self.direction=="down":
self.direction="up"
myBall=Ball("red","small","down")
print "I just created a ball."
print "My ball is",myBall.size
print "My ball is",myBall.color
print "My ball's direction is",myBall.direction
print "Now I'm going to bounce the ball"
print
myBall.bounce()
print "Now the ball's direction is",myBall.direction
这是正确的运行结果:
======================= RESTART: H:\python\bounce1.py =======================
I just created a ball.
My ball is small
My ball is red
My ball's direction is down
Now I'm going to bounce the ball
Now the ball's direction is up
Atas ialah kandungan terperinci 详解python中的TypeError错误解决办法. Untuk maklumat lanjut, sila ikut artikel berkaitan lain di laman web China PHP!