dict common operations

dict is a common data structure in the python, which master should try to use
"""
    Initializing a dict of four ways:
    1. dict () -> Create an empty dict
    2. dict(mapping) -> new dictionary initialized from a mapping object's
       (key, value) pairs
    3. dict(iterable) -> new dictionary initialized as if via:
       d = {}
       for k, v in iterable:
           d[k] = v
    4.  dict(**kwargs) -> new dictionary initialized with the name=value pairs
       in the keyword argument list.  For example:  dict(one=1, two=2)
   """

# The first way 
D = dict ()

# 第二种方式
# d = {"person": {"name": "admin", "age": 12},
#      "animal": {"name": "gaodan", "age": 3},
#      }

# Third mode 
D = dict ({ " name " : " ADMIN " })
 Print (D)

# Fourth embodiment 
D = dict (name = ' ADMIN ' , Age = 12 is )

print(type(d))
print("原字典:%s" % d)  # {'name': 'admin', 'age': 12}

# Clear, emptied 
# d.clear () 
# Print (D)


# Copy shallow copy


new_d = d.copy ()
 Print ( " Copy the new dictionary:% S " % new_d)   # { 'name': 'ADMIN', 'Age':} 12 is 

new_d [ ' name ' ] = ' the root ' 
Print ( ' Copy dictionary after revision:% S ' % new_d)   # Copy dictionary after revision: { 'name': 'the root', 'Age': 12 is} 
Print ( " original dictionary after modification:% S " % D)   # { 'name': 'ADMIN', 'Age':} 12 is 
# summary: copy shallow copy simple data structures are created when a new object, modify the value of the new dict, without causing the original value of dict Variety

print('*' * 50)

d = {"person": {"name": "admin", "age": 12},
     "animal": {"name": "gaodan", "age": 3}
     }

print(d)  # {'person': {'name': 'admin', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}
new_d = d.copy()
new_d['person']['name'] = 'root'

print(new_d)  # {'person': {'name': 'root', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}
print(d)  # {'person': {'name': 'root', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}

# Summary: shallow copy: copy a shallow copy complex data structures, the only point of this reference complex data structures, and do not create a new object so modified when new_d the value of the new dict, the value of original dict is also changed. If it is a simple data structure, the absence of such, the above examples also

"""
     Deep copy of the required import copy python
     copy.deepcopy()
"""

print('--------------------deep copy------------------')
import copy

d = {"person": {"name": "admin", "age": 12},
     "animal": {"name": "gaodan", "age": 3}
     }
print(d)
dd = copy.deepcopy(d)
print(dd)  # {'person': {'name': 'admin', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}
dd['person']['name'] = '哑巴'
print(dd)  # {'person': {'name': '哑巴', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}
print(d)  # {'person': {'name': 'admin', 'age': 12}, 'animal': {'name': 'gaodan', 'age': 3}}


# Fromkeys, create a new dict, key values in the sequence 
D = dict.fromkeys ([ ' Jet ' , ' Lily ' ], { " name " : " MAM " })
 Print (D) # { 'Jet' : { 'name': 'mam '}, 'lily': { 'name': 'mam'}}

# . GET values, is not None 
value = d.get ( " Jet " )
 Print (value) # { 'name': 'MAM'} 

D = { " name " : ' ADMIN ' , ' Age ' : 12 is }

# Items方法 
k = d.items ()
 for k in and k:
      print (k, v)

keys = d.keys()
print(keys)  # dict_keys(['name', 'age'])


# POP (key) corresponding to the specified key is removed kV 
# value = d.pop ( 'name') # key to delete the name 
# Print (value) ADMIN # 
# Print (D) {# 'Age':} 12 is


# Popitem removed, followed by one Item 
popitem = d.popitem ()
 Print (popitem)   # ( 'Age', 12 is) removed the mapping relationship 
Print (D)   # { 'name': 'ADMIN'} d left this stuff



d = {"name":'admin','age':12}

# SetDefault (k, v), if there are in the original dict k, returns to the original dict k -> v, otherwise it will k, v dict added to the 
default_value = d.setdefault ( ' FEMALE ' , ' Ali ' )
 Print (default_value)
 Print (D)   # { 'name': 'ADMIN', 'Age': 12 is, 'FEMALE': 'Ali'} 

default_value = d.setdefault ( ' FEMALE ' , ' JD ' )
 Print (default_value)   # Ali 
Print (D)   # { 'name': 'ADMIN', 'Age': 12 is, 'FEMALE': 'Ali'}

# Update to add elements dict. 
# The first method uses the update, the attention key is not quoted 
# d.update (Book = 'Python', = Teacher 'Dog') 
Print (D)   # { 'name': ' admin ',' age ': 12 ,' female ':' ali ',' book ':' python ',' teacher ':' dog '}

# Using the second embodiment of the update 
d.update ([( ' Teacher ' , ' Dog ' ), { ' Book ' , ' Java ' }])   # Good like hanging 
Print (D) # { 'name': ' admin ',' age ': 12 ,' female ':' ali ',' teacher ':' dog ',' book ':' java '}


# values

vs = d.values()
print(vs)  #dict_values(['admin', 12, 'ali', 'dog', 'java'])
dict common operations

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