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41 lines
1.5 KiB
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41 lines
1.5 KiB
Plaintext
Content-Type: text/x-zim-wiki
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Wiki-Format: zim 0.4
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Creation-Date: 2012-10-04T13:21:05+08:00
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====== dict ======
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Created Thursday 04 October 2012
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Help on class dict in module __builtin__:
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class dict(object)
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| dict() -> new empty dictionary
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| dict(mapping) -> new dictionary initialized from **a mapping object**'s #mapping为__一个__pairs对象
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| (key, value) pairs
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| dict(iterable) -> new dictionary initialized as if via:
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| d = {}
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| for **k, v** in iterable: #迭代器对象每次返回的元素必须是一个容器类型，__容器中元素的个数为2__.**如[a,b], **~~"ab"~~**,(a,b)**
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| d[k] = v
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| dict(__**kwargs)__ -> new dictionary initialized with the name=value pairs
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| in the keyword argument list. For example: dict(one=1, two=2)
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| Methods defined here:
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>>> dict(__[('sape', 4139), ('guido', 4127), ('jack', 4098)]__)
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{'sape': 4139, 'jack': 4098, 'guido': 4127}
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>>> dict([(x, x**2) for x in (2, 4, 6)]) # use a list comprehension
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{2: 4, 4: 16, 6: 36}
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>>> dict(sape=4139, guido=4127, jack=4098)
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{'sape': 4139, 'jack': 4098, 'guido': 4127}
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tel = {'jack': 4098, 'sape': 4139}
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>>> dc=dict(["df","12"]);dc #["df","12"]为一科迭代对象，每次返回的元素为两个字符的str，所以可以被unpack给key,value
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{'1': '2', 'd': 'f'}
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>>> dc=dict(["df",__"123"__]);dc
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Traceback (most recent call last):
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File "<stdin>", line 1, in <module>
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ValueError: dictionary update sequence element __#1 has length 3; 2 is required__
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>>>
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