Python字典和集合

2017-10-20  本文已影响18人  Ke爺

1 字典基础操作

1.1 创建字典

1.2 访问字典

>>> for eachKey in aDict:
...     print 'key=%s, value=%s' % (eachKey, aDict[eachKey])
...
key=age, value=25
key=name, value=ke
>>> print '%(name)s' % aDict
ke

1.3 更新字典

>>> print aDict
{'age': 25, 'name': 'ke'}
>>> aDict['age'] = 22
>>> print aDict
{'age': 22, 'name': 'ke'}
>>> aDict['email']='allenouyangke@icloud.com'
>>> print aDict
{'age': 22, 'name': 'ke', 'email': 'allenouyangke@icloud.com'}
>>>

1.4 删除字典

>>> del aDict['email']
>>> print aDict
{'age': 22, 'name': 'ke'}
>>> aDict.pop('age')
22
>>> print aDict
{'name': 'ke'}
>>> aDict.clear()
>>> print aDict
{}

1.5 字典操作符

>>> aDict = {'name': 'ke', 'age': 25}
>>> print aDict
{'age': 25, 'name': 'ke'}
>>> 'name' in aDict
True
>>> 'ke' in aDict
False
>>>

2 字典相关函数

2.1 作用于字典的函数

>>> print aDict
{'age': 25, 'name': 'ke'}
>>> len(aDict)
2
>>> hash(3)
3
>>> hash([])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'
>>>

2.2 字典内建方法

>>> print aDict
{'age': 25, 'name': 'ke'}
>>> bDict = aDict.copy()
>>> print bDict
{'age': 25, 'name': 'ke'}
>>> bDict['name'] = 'yuyu'
>>> print bDict
{'age': 25, 'name': 'yuyu'}
>>> print aDict
{'age': 25, 'name': 'ke'}
>>>
>>> print aDict
{'age': 25, 'name': 'KE'}
>>> aDict.get('name', 'not found')
'KE'
>>> aDict.get('email', 'not found')
'not found'
>>>
>>> print aDict
{'age': 25, 'name': 'KE'}
>>> aDict.setdefault('age', 20)
25
>>> aDict.setdefault('iphone', 13570319584)
13570319584
>>> print aDict
{'age': 25, 'name': 'KE', 'iphone': 13570319584}
>>>

3 集合

3.1 集合类型

>>> s1 = set('hello')
>>> s2 = frozenset('hello2')
>>> s1
set(['h', 'e', 'l', 'o'])
>>> s2
frozenset(['h', '2', 'e', 'l', 'o'])
>>>

3.2 集合类型操作符

3.3 集合内建方法


上一篇 下一篇

猜你喜欢

热点阅读