Python核心编程——第四章Python对象

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三种方法查看数字数据的类型：

[1] isinstance 可读性更好
#! /usr/bin/env python'''typechk.py'''def displayNumType(num): print num, 'is', if isinstance(num, (int, long, float, complex)): print 'a number of type:', type(num).__name__ else: print 'not a number at all!'displayNumType(-69)displayNumType(99999999999999999999L)displayNumType(99999999999999999999)displayNumType(98.6)displayNumType(-5.2+1.9j)displayNumType('aaa')######## output#######-69 is a number of type: int99999999999999999999 is a number of type: long99999999999999999999 is a number of type: long98.6 is a number of type: float(-5.2+1.9j) is a number of type: complexaaa is not a number at all!

[2] 调用两次type

#! /usr/bin/env python'''typechk.py'''def displayNumType(num): print num, 'is', if type(num)==type(0): print 'an integer' elif type(num)==type(0L): print 'a long' elif type(num)==type(0.0): print 'a float' elif type(num)==type(0+0j): print 'a complex number' else: print 'not a number at all!'displayNumType(-69)displayNumType(99999999999999999999L)displayNumType(99999999999999999999)displayNumType(98.6)displayNumType(-5.2+1.9j)displayNumType('aaa') ######## output#######-69 is an integer99999999999999999999 is a long99999999999999999999 is a long98.6 is a float(-5.2+1.9j) is a complex numberaaa is not a number at all!

[3] import types

#! /usr/bin/env pythonimport types'''typechk.py'''def displayNumType(num): print num, 'is', if type(num)==types.IntType: print 'an integer' elif type(num)==types.LongType: print 'a long' elif type(num)==types.FloatType: print 'a float' elif type(num)==types.ComplexType: print 'a complex number' else: print 'not a number at all!', print 'but, it is', if type(num)==types.StringType: print 'a string' displayNumType(-69)displayNumType(99999999999999999999L)displayNumType(99999999999999999999)displayNumType(98.6)displayNumType(-5.2+1.9j)displayNumType('aaa')######## output#######-69 is an integer99999999999999999999 is a long99999999999999999999 is a long98.6 is a float(-5.2+1.9j) is a complex numberaaa is not a number at all! but, it is a string