Python common data types-dictionaries

First, define a dictionary

Created with {}, each key value in the dictionary is key=>value with a colon : split, separated by commas , between each key-value pair 

shenyang={' name ': ' Shenyang ', ' age ': ' Sex ': ' Male ', ' addr ': ' Tian Tong Yuan ', ' qq ': ' 19322 ', ' email ': ' [email protected] '

Second, the judgment

Non-NULL is true, not 0 is true

For example: (if the contents of the E variable have the data true, the empty print is false)

E= "

If e:
    Print ("true")
Else
    Print ("false")

C. Increase (the dictionary is unordered)

shenyang={' name ': ' Shenyang ', ' age ': ' Sex ': ' Male ', ' addr ': ' Tian Tong Yuan ', ' qq ': ' 19322 ', ' email ': ' [email protected] '

shenyang[' phone ']= ' 3333 ' #往字典里面增加k-V is python:3333

Shenyang.setdefault (' age ', $) #如果key存在, take the values of the original key, that is, age still shows 18

Iv. modification

shenyang[' age ']=38

V. Delete

Shenyang.pop (' girlfriend ') #指定key删除 deleted when key does not exist will be an error

Del shenyang[' girlfriend '] #用del来删, deleted when key does not exist will error

Shenyang.clear () #清空字典

Shenyang.popitem () #随机删除一个key

Six, the value

Print (shenyang[' name '])

Print (Shenyang.get (' name ')) #get后面可以加默认值, if the default is None, the other default values can be displayed

yaoyuan={' Chouyan ': ' 1 package ', ' name ': ' Yao Yuan '}

Shenyang.update (Yaoyuan) #把一个字典加到另外一个字典里面

For K,v in (Shenyang). Items (): #用items方法来循环获取k和value

info =  [
   {
      ' Xiaohei ':
         {
            ' Money ': 10000,
            ' Cars ': [' ben-z ', ' Audi ', ' BMW '],
            ' Info ': {
               ' Phone ': 186212312,
               ' Age ': 36,}
         }
    },
   {' Xiaohong ':
       {
          ' House ': {
             ' Chaoyang ': 2,
             ' Haidian ': 3,
             ' Changping ': 5
          },
          ' LAN ': [' ch ', ' en ', ' JP '],
       }
    }
]
info[0][' Xiaohei ' [' Cars '].append (' Baoshijie ')
info[0][' Xiaohei ' [' Info '] [' addr '] = ' sdfsdf '
info[1][' Xiaohong ' [' House '] [' Haidian '] +=2# in Haidian 3 plus 2 is 5
info[1][' Xiaohong ' [' Sex ']= ' women ' #在小红加性别K

Seven, the way of efficient circulation dictionary

#coding =utf-8
D={' A ': 1, ' B ': 2}
Print (D.items ()) #字典转换了list
For k,v in D.items ():
    Print (K,V)
For K in D:
    Print (K,d.get (k)) #先找k再根据k找value a 1 B 2

Python common data types-dictionaries