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小編給大家分享一下python中有沒(méi)有幫助函數(shù),相信大部分人都還不怎么了解,因此分享這篇文章給大家參考一下,希望大家閱讀完這篇文章后大有收獲,下面讓我們一起去了解一下吧!
python中的dir()函數(shù)是一個(gè)非常重要的函數(shù),它可以幫助我們查看函數(shù)的功能和特性。
中文說(shuō)明:不帶參數(shù)時(shí),返回當(dāng)前范圍內(nèi)的變量、方法和定義的類型列表;帶參數(shù)時(shí),返回參數(shù)的屬性、方法列表。如果參數(shù)包含方法__dir__(),該方法將被調(diào)用。如果參數(shù)不包含__dir__(),該方法將大限度地收集參數(shù)信息。
參數(shù)object: 對(duì)象、變量、類型。
版本:該函數(shù)在python各個(gè)版本中都有,但是每個(gè)版本中顯示的屬性細(xì)節(jié)有所不同。使用時(shí)注意區(qū)別。
例如
>>>import struct >>>dir() # show the names in the module namespace ['__builtins__','__doc__','__name__','struct'] >>>dir(struct) # show the names in the struct module ['Struct','__builtins__','__doc__','__file__','__name__', '__package__','_clearcache','calcsize','error','pack','pack_into', 'unpack','unpack_from'] >>>class Shape(object): def __dir__(self): return ['area','perimeter','location'] >>> s= Shape() >>>dir(s)
['area', 'perimeter', 'location'] Note Because dir() is supplied primarily as a convenience for use at an interactive prompt, it tries to supply an interesting set of names more than it tries to supply a rigorously or consistently defined set of names, and its detailed behavior may change across releases. For example, metaclass attributes are not in the result list when the argument is a class.
代碼實(shí)例(更多學(xué)習(xí)內(nèi)容,請(qǐng)點(diǎn)擊創(chuàng)新互聯(lián))
>>>dir() ['__builtins__','__doc__','__name__','__package__'] >>>import struct >>>dir() ['__builtins__','__doc__','__name__','__package__','struct'] >>>dir(struct) ['Struct','__builtins__','__doc__','__file__','__name__','__package__','_clearcache','calcsize','error','pack', 'pack_into','unpack','unpack_from'] >>>class Person(object): ... def __dir__(self): ... return ["name","age","country"] ... >>>dir(Person) ['__class__','__delattr__','__dict__','__dir__','__doc__','__format__','__getattribute__','__hash__','__init__', '__module__','__new__','__reduce__','__reduce_ex__','__repr__','__setattr__','__sizeof__','__str__','__subclasshook__', '__weakref__'] >>> tom= Person() >>>dir(tom) ['age','country','name']
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