Summary of operation usage for Python dictionaries

Basic syntax:

Dict = {' Ob1 ': ' Computer ', ' ob2 ': ' Mouse ', ' ob3 ': ' Printer '}

Skills:

Dictionary contains list: dict={' yangrong ': [' ['] ', ' IT '], ' xiaohei ': ['] ', ' DotA '}

Dictionary contains dictionary: dict={' yangrong ': {"Age": "" "," "Job": "IT"}, "Xiaohei": {"' Age ': ' '", ' job ': ' DotA '}}

Available commands:

root@yangrong:~# Cd/python

root@yangrong:/python# python

Python 2.7.5+ (default, Sep 19 2013,13:48:49)

[GCC 4.8.1] on linux2

Type "Help", "copyright", "credits" or "license" for moreinformation.

>>> Import Tab

>>> d={}

>>> d.

D.class (D.ge (D.len (D.setitem (D.has_key (D.setdefault (

D.CMP (D.getattribute (d.lt (d.sizeof (D.items (D.update (

D.contains (D.getitem (D.ne (D.str (D.iteritems (D.values (

D.delattr (d.gt (D.new (D.subclasshook (D.iterkeys (D.viewitems (

D.delitem (D.hash d.reduce (D.clear (D.itervalues (D.viewkeys (

D.doc D.init (D.REDUCE_EX (D.copy (D.keys (D.viewvalues (

D.eq (D.iter (D.repr (D.fromkeys (D.pop (

D.format (D.le (D.setattr (D.get (D.popitem (

>>> d.

Add dictionary elements

>>> nameinfo={}

>>> nameinfo[' A1 ']= ' Yangrong ' #若字典里有a1主键, then overwrite the original value, no, add

>>> Nameinfo

{' A1 ': ' Yangrong '}

Traverse Dictionary primary key and key value

>>> for K, Value Innameinfo.items ():

... print K,value

...

A1 Yangrong

View dictionary all primary keys

>>> dict = {' Ob1 ': ' Computer ', ' ob2 ': ' Mouse ', ' ob3 ': ' Printer '}

>>>

>>>

>>> Dict.keys ()

[' Ob2 ', ' ob3 ', ' ob1 ']

Determine if the primary key is in the dictionary

>>> Dict.keys ()

[' Ob2 ', ' ob3 ', ' ob1 ']

>>> dict.has_key (' ob2 ') #或 ' ob2 ' in Dict

True

>>> dict.has_key (' ob4 ')

False

Some people use cyclic methods to judge

For key in Dict.keys ():

But this approach is not simple enough,

View dictionary all key value contents

>>> dict = {' Ob1 ': ' Computer ', ' ob2 ': ' Mouse ', ' ob3 ': ' Printer '}

>>> dict.values ()

[' Mouse ', ' printer ', ' computer ']

List all items

>>> Dict.items ()

[(' Ob2 ', ' Mouse '), (' Ob3 ', ' Printer '), (' Ob1 ', ' computer ')]

Empty dictionary

>>> Dict.clear ()

>>> Dict

{}

Copy Dictionary

>>> Dict

{' Ob2 ': ' Mouse ', ' ob3 ': ' Printer ', ' ob1 ': ' Computer '}

>>> a=dict

>>> A

{' Ob2 ': ' Mouse ', ' ob3 ': ' Printer ', ' ob1 ': ' Computer '}

>>> b=dict.copy ()

>>> b

{' Ob2 ': ' Mouse ', ' ob3 ': ' Printer ', ' ob1 ': ' Computer '}

Compare dictionaries

>>> CMP (A, B)

First compare the primary key length, then compare the key size, then compare the key value size, (first large return 1, small return-1, like return 0)

Update dictionary

>>>dict={' Yangrong ': {"age": "All", "job": "IT"}, "Xiaohei": {"' Age ': ' '", ' job ': ' DotA '}}

>>> Dict

{' Xiaohei ': Set (["' Age ': ' ['] ', ' job ': ' DotA '"]), ' Yangrong ': {' age ': ' ' ", ' job ': ' IT '}}

>>> dict[' Xiaohei ']=111 #修改一级字典

>>> Dict

{' Xiaohei ': 111, ' Yangrong ': {' age ': ' + ', ' job ': ' IT '}}

>>> dict[' Yangrong ' [' Age ']=25 #修改二级字典

>>> Dict

{' Xiaohei ': 111, ' Yangrong ': {' age ': ' Job ': ' IT '}}

>>> dict={' yangrong ': [' + ', ' IT '], ' xiaohei ': ['] ', ' DotA '}

>>>dict[' Xiaohei '][1]= "Dota2" #修改字典中列表某项, 1 is the 2nd string in the representation list.

>>> Dict

{' Xiaohei ': [' + ', ' dota2 '], ' yangrong ': [' ['] ', ' IT ']}

Delete a dictionary element

>>> Dict

{' Xiaohei ': [' + ', ' dota2 '], ' yangrong ': [' ['] ', ' IT ']}

>>> del dict[' Xiaohei '] #删除xiaohei键值

>>> Dict

{' Yangrong ': [' + ', ' IT ']}

>>> Dict

{' Yangrong ': [' + ', ' IT ']}

>>>

>>> del dict[' Yangrong '][1] #删除yangrong主键的每2字值

>>> Dict

{' Yangrong ': [' 23 ']}

Delete entire dictionary

>>> Dict

{' Yangrong ': [' 23 ']}

>>> dict.clear () #同del dict

>>> Dict

{}

Cut a string into a list

>>> s= "Hello World Bye"

>>> s.split () #用于把有规律的文本, after reading, use the list to modify, and then write to the file.

[' Hello ', ' world ', ' Bye ']

Convert a list to a string

S.split (str, ') #将string转list, with a space slice

Storage dictionaries (pickle serialization)

#需导入pickle模块 Import Pickle

Deposit the contents of a dictionary into a file

F=file (' Data.txt ', ' WB ') #新建文件data. txt, ' WB ', b is open block file, useful for device files

Pickle.dump (a,f) #把a序列化存入文件

F.close ()

Read the contents into a dictionary (deserialization)

A=open (' data.txt ', ' RB ') #打开文件

Print Pickle.load (a) #把内容全部反序列化