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This article mainly introduces "how to understand the basic operation of Python dictionary". In daily operation, I believe many people have doubts about how to understand the basic operation of Python dictionary. Xiaobian consulted all kinds of materials and sorted out simple and easy operation methods. I hope to help you answer the doubts about "how to understand the basic operation of Python dictionary"! Next, please follow the small series to learn together!

>> dir(dict) #View properties and methods of field dict ['__class__','__contains__','__delattr__','__delitem__','__dir__','__doc__','__eq__','__format__','__ge__','__getattribute__','__getitem__','__gt__','__hash__','__init__','__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy','fromkeys',' get','items',' keys','pop',' popitem','setdefault',' update','values'] DictionaryCommonly-used function description: dict1.clear() Empty dictionary dict1.copy() Copy dictionary dict1.get (k,[default]) Get the value of k, if it doesn't exist, return defaultdict1.items() Get the iterator consisting of keys and values dict1.keys() Get the iterator of keys dict1.pop(k) Delete k: v Member pair dict1.update(dict2) Update key pairs in dictionary dict2 to dict1.values() iterator to obtain values in dict1 dict1.fromkeys(k1,v1) Rebuilds dictionary with values given in list or tuple k1 as keys, default value is v1dict1.popitem() deletes any key pair from dictionary and returns it dict1.setdefault (k,default) If there is a key named k in the dictionary, return the corresponding value; otherwise, establish a k:default key pair in the dictionary. Basic operations of the dictionary: >> d1 = {'a': 1,' b': 2,'c': 3,' d': 4}>> d1{'a': 1, ' b': 2, 'c': 3, ' d': 4}>>> d1.get('a')1>>> d1.get ('f',' 123')#Get keys that don't exist, return 123'123'>> d1.get('f')#Get keys that don't exist, return no value without setting optional parameters>> d1 ('d')#Get keys by key name, 4>> d1 ('f ')#Traceback (most recent call last): File "", line 1, in d1['f']KeyError: 'f'>>> d1.items() #Returns all key-value pairs in the dictionary dict_items ([('a ', 1),('b', 2),('c ', 3), ('d', 4)])>> d1.keys() #Returns all dictionary keys dict_keys (['a',' b','c',' d'])>>> d1.values() #Returns all dictionary values dict_values ([1, 2, 3, 4])>>> d1.update ({'d':999}) #Update existing key-value pairs 'd': 4>> d1{' a': 1, 'b': 2, ' c': 3, 'd': 999}>> d1.update with a dictionary {'d': 999}({'f': 1000}) #Use a dictionary {' f': 1000} to update key pairs that do not exist in d1 (equal to adding key pairs)>> d1{'a': 1, ' b': 2, 'c': 3, ' d': 999, 'f': 1000} At this point, the study of "how to understand the basic operations of Python dictionaries" is over. I hope I can solve your doubts. Theory and practice can better match to help everyone learn, go and try it! If you want to continue learning more relevant knowledge, please continue to pay attention to the website, Xiaobian will continue to strive to bring more practical articles for everyone!

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