Python 3.0 dictionary Additions and deletions

First, the definition of the dictionary method:

1. dic = {' name ': ' Karen ', ' age ': $, ' hobby ': ' Girl ', ' Is_handsome ': True}

Print (DIC) #==>{' name ': ' Karen '}

DIC = {' name ': ' Karen ', ' age ': $, ' hobby ': {' name ': ' Xu ', ' Age ': $}, ' Is_handsome ': True}

2, Dic=dict ((' Name ', ' Karen '),) | |   Dic=dict ([' Name ', ' Karen '],)) | |      Dic=dict ([[' Name ', ' Karen '],]) | | Dic=dict ([' Name ', ' Karen '),])

Print (DIC) #==>{' name ': ' Karen '}

Two main features of the dictionary: disorder, key unique

Dictionary keys can only have immutable elements >>>>> immutable types: Integer, string, tuple mutable type: list, dictionary

Second, increase

1. dic1={' name ': ' Karen '}

dic1[' age ']=18

Print (DIC1) #==>{' name ': ' Karen ', ' Age ': 18}

2, Dic1.sendefault (' Age ', "#如果有这个键值对"), do nothing and return the value, if not, increase and return the value

Print (DIC1)

Third, find

1. dic={' name ': ' Karen ', ' Age ': 18}

Print (dic[' name ']) #==>karen

2, Print (Dic.keys ()) #==> only printing keys

The type is Dict_keys type, not a list

Print (Dic.values ()) #==> prints only values

Print (Dic.items ()) #==> printing key-value pairs

Iv. Change of

1. dic={' name ': ' Karen ', ' Age ': 18}

dic[' age ']=33

Print (DIC) #==>{' name ': ' Karen ', ' Age ': 33}

2. dic={' name ': ' Karen ', ' Age ': 18}

Dic1={' a ': ' AAA ', ' B ': ' BBB '}

Dic.update (DIC1) #若有值则替换

V. Delete

1. dic={' name ': ' Karen ', ' Age ': 18}

del dic (' name ')

Print (DIC) #==>dic={' age ': 18} Delete entire key-value pairs

2, Dic.clear ()

Print (DIC) #==>dic={}

3. Dic.pop (' age ')

Print (DIC) #==>dic={' age ': 18} Deletes the entire key-value pair and returns the value as a return value

4, A=dic.popitem ()

Print (A,dic) #随机删除

Vi. other operations and the methods involved

1, Dic=dict.fromkeys ([' host1 ', ' host2 ', ' host3 '], ' test ')

Print (DIC) #==>{' host1 ', ' host2 ', ' host3 ', ' Test '} Initialize dictionary with keys, no value

2, Dic=[5: ' 555 ', 2: ' 666 ', 4: ' 444 ']

Print (sorted (Dic.items ()))

Print (sorted (Dic.keys ()))

Print (sorted (dic.values ()))

3. dic={' name ': ' Karen ', ' Age ': 18}

For I in DIC:

Print (I,dic[i])

Python 3.0 dictionary Additions and deletions