Python入门的36个例子 之 35
源代码下载:下载地址在这里
# 039
while True:
try:
x = int(raw_input('Input a number:'))
y = int(raw_input('Input a number:'))
z = x / y
except ValueError, ev:
print 'That is not a valid number.', ev
except ZeroDivisionError, ez:
print 'Divisor is zero:', ez
except:
print 'Unexpected error.'
raise
else:
print 'There is no error.'
break
# end of try
# end of while
print x,'/',y,'=',x/y
output:
Input a number:w
That is not a valid number. invalid literal for int() with base 10: 'w'
Input a number:9
Input a number:0
Divisor is zero: integer division or modulo by zero
Input a number:9
Input a number:3
There is no error.
9 / 3 = 3
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# 004
# 利用三引号(''' or """)可以指示多行字符串
print '''line1
line2
line3'''
# 另外,你还可以在三引号中任意使用单引号和双引号
print ''' "What's up? ," he replied.'''
# 否则,你好使用转义符来实现同样的效果
# 还是使用三引号好,不然就破坏了视觉美了
print ' \"Wha ......
模块这东西好像没什么好讲的,无非是保存一份文件,然后在另一份文件中用import 和from ** import **(*)就行了。
这一章主要讲到了细节,导入模块Python里面是什么处理的,import 和 from ** import **有什么不一样。还有就是增加了reload()这个函数的使用说明。
以前看到哪里说尽量使用import而不要使用from ** import * ......
源代码下载:下载地址在这里
# 033
class Person:
age = 22
def sayHello(self): # 方法与函数的区别在于需要一个self参数
print 'Hello!'
# end of def
# end of class # 这是我良好的编程风格
p = Person()
print p.age
p.sayHello()
output:
22
Hello! ......
源代码下载:下载地址在这里
A Byte Of Python
中关于继承有这样的文字:
Suppose you want to write a program which has to keep track of the
teachers and students in a college. They have some common
characteristics such as name, age and address. They also have specific
characteristics such as sala ......