# Python3 Dictionary Operations

Source: Internet
Author: User

`字典：创建方式： 1、正常创建 a = {‘name‘: ‘azj‘, ‘age‘: 23, ‘mail‘: ‘[email protected]‘} 2、通过工厂函数dict创建 a = dict(([‘name‘, ‘azj‘], [‘age‘, 23], [‘email‘, ‘[email protected]‘])) 3、 a = {}.fromkeys((‘azj‘, ‘tom‘, ‘lili‘), 11) {‘azj‘: 11, ‘tom‘: 11, ‘lili‘: 11}>>> a = {‘name‘: ‘azj‘, ‘age‘: 23}>>> a{‘name‘: ‘azj‘, ‘age‘: 23}>>> ‘%(name)s:%(age)s‘ % a‘azj:23‘`

Modify:
adict = {' name ': ' Azj ', ' Age ': 26}

{' name ': ' Azj ', ' Age ': 26}
>> adict[' age '] = 22
{' name ': ' Azj ', ' age ': 22}
>> adict[' phone '] = ' 15901037927 ' #字典里有这个字段修改, no then add this field
{' name ': ' Azj ', ' age ': ' Phone ': ' 15901037927 '}

Delete:
{' name ': ' Azj ', ' age ': ' Phone ': ' 15901037927 '}

>> adict.pop (' name ') #pop默认弹出并删除最后一项, the dictionary should be unordered in the dictionary so you need to specify the field information that pops up
' Azj '
{' Age ': \$, ' phone ': ' 15901037927 '}
(' phone ', ' 15901037927 ')
{' Age ': 22}
{}

``len(字典)    #统计字典内的元素数目>>> len(adict)2``

Copy of Dictionary:

>> a = {' name ': ' Azj ', ' age ': 23}
>> A
{' name ': ' Azj ', ' age ': 23}
>> B = A #内容赋值, pointing to the same memory space
>> b
{' name ': ' Azj ', ' age ': 23}
>> A
{' name ': ' Azj ', ' age ': 23}
>> ID (a)
140165656248536
>> ID (b)
140165656248536
>> C = a.copy ()
>> C
{' name ': ' Azj ', ' age ': 23}
>> ID (c)
140165656248752

Xxx.get (' key ', []) #列出字典的value, if no key is returned by default, none, custom return information []

>> Dict
{' name ': ' Azj ', ' Age ': 26}
>> dict.pop (' age ')
26
>> Dict
{' name ': ' AZJ '}
>> dict.get (' name ')
' Azj '
>> dict.get (' age ')

Xxx.setdefault () #当字典里面没有该值的情况下进行添加, some words cannot be added

>> Dict
{' name ': ' AZJ '}
>> dict.setdefault (' age ', 26)
26
>> Dict
{' name ': ' Azj ', ' Age ': 26}
>> dict.setdefault (' age ', 25)
26
>> Dict
{' name ': ' Azj ', ' Age ': 26}

>> Dict.keys () #列出当前字典所有的key
Dict_keys ([' Name ', ' age '])
>> dict.values () #列出当前字典的所有value
Dict_values ([' AZJ ', 26])

>> Dict.items () #列出当前字典的key和value
Dict_items ([' Name ', ' Azj '), (' Age ', 26)])

# #key, Value rollover

>> {Value:key for key, value in Dict.items ()}
{' AZJ ': ' Name ',: ' Age '}
#互换的时候注意, the same value can cause element loss
>> a = {}.fromkeys (' Tom ', ' Bob ', ' Lili '), 18)
>> A
{' Tom ': ' Bob ': Lili ': 18}
>> {Val:key for key, Val in A.items ()}
{: ' Lili '}

Stitching of dictionaries:

>> a = {' name ': ' AZJ '}
>> A
{' name ': ' AZJ '}
>> B = {' Age ': 26}
>> A.update (b)
>> A
{' name ': ' Azj ', ' Age ': 26}

Python3 Dictionary Operations

Related Keywords:

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