python中如何判断一个变量的数据类型?(原创)
import types
type(x) is types.IntType # 判断是否int 类型
type(x) is types.StringType #是否string类型
.........
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超级恶心的模式,不用记住types.StringType
import types
type(x) == types(1) # 判断是否int 类型
type(x) == type('a') #是否string类型
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使用内嵌函数:
isinstance
(
object, classinfo
)
Return true if the object
argument is an instance
of the classinfo
argument, or of a (direct or indirect)
subclass thereof. Also return true if classinfo
is a type
object and object
is an object of that type. If object
is not a class instance or an object of the given type, the function
always returns false. If classinfo
is neither a class
object nor a type object, it may be a tuple of class or type objects,
or may recursively contain other such tuples (other sequence types are
not accepted). If classinfo
is not a class, type, or
tuple of classes, types, and such tuples, a TypeError
exception is raised. Changed in version
2.2: Support for a tuple of type information was added.
Python可以得到一个对象的类型 ,利用type函数:
>>>lst = [1, 2, 3]
>>>type(lst)
<type 'list'>
不仅如此,还可以利用isinstance函数,来判断一个对象是否是一个已知的类型。
isinstance说明如下:
isinstance(object, class-or-type-or-tuple) -> bool
Return whether an object is an instance of a class or of a subclass
thereof.
With a type as second argument, return whether that is the object's
type.
The form using a tuple, isinstance(x, (A, B, ...)), is a shortcut
for
isinstance(x, A) or isinstance(x, B) or ... (etc.).
其第一个参数为对象,第二个为类型名或类型名的一个列表。其返回值为布尔型。若对象的类型与参数二的类
相关文档:
英文版Dive in python可以在下面找到中文翻译http://linuxtoy.org/docs/dip/toc/index.html
模块的__name__,当模块被import时,其为模块的名字,当模块作为main执行的时候,其为__main__
词典的key是大小写敏感的。
List也支持重载+操作,用于将两个list连接起来,并返回一个List,因此它没有extended执行高效。list也+ ......
关键字: python
Python、Unicode和中文[转]
python的中文问题一直是困扰新手的头疼问题,这篇文章将给你详细地讲解一下这方面的知识。当然,几乎可以确定的是,在将来的版本中,python会彻底解决此问题,不用我们这么麻烦了。
先来看看python的版本:
>>> import sys
>> ......
>>> import time
>>> import datetime
>>>
now = time.localtime()
>>> now
(2006, 4, 30, 18, 7, 35,
6, 120, 0)
>>> type(now)
<type 'time.struct_time'>
>>>
str_now = time.strftime("%m/%d/%Y %X", now )
>>>
str_n ......