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<\/p>\nJust like a set, a dictionary is an unordered collection. A dictionary represents a collection of key:value pairs. In other words, we can use a data type to reference an item instead of just the index of the item. These key:value pairs are separated by commas. Dictionaries are declared in curly brackets. Each item can be a collection item also. Some examples are given below:<\/p>\n
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In dict2 above, note that we used the key of “3” as a string instead of a number. dict3 shows how a dictionary can store collection objects.<\/p>\n
The following operators work on dictionaries:<\/p>\n
[] – indexing operator<\/strong><\/p>\n This is used to get the value of a key that exists in the dictionary. If the key does not exist then an error is thrown.<\/p>\n in – search operator<\/strong><\/p>\n The in operator returns true if a key exists in the dictionary else false<\/p>\n del – delete dict[key]<\/strong><\/p>\n This deletes a key:value pair from the dictionary. If the key does not exist, an error is thrown<\/p>\n len – len(dict)<\/strong><\/p>\n This returns the count of items in the dictionary. If there are no items then a length of zero is returned.<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n The following methods are available for dictionaries:<\/p>\n keys – dict.keys()<\/strong><\/p>\n Returns all the keys in the dictionary as a list.<\/p>\n values – dict.values()<\/strong><\/p>\n Returns all the values int the dictionary as a list<\/p>\n items – dict.items()<\/strong><\/p>\n Returns all the key:value pairs as a list. Each pair is a list within the main list<\/p>\n get – dict.get(key, alternative)<\/strong><\/p>\n Gets the value of a key. If a key is not found and alternative is not specified then it returns None. If alternative is specified then it returns the alternative value.<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n In the items method you can see that the pairs are returned as a list with each pair item returned as a list. So using\u00a0 list indexing we can refer to the first pair as list[0] and then the first item within the first pair as list[0][1]<\/p>\n <\/p>\n In the next post we will look at Basic Input and Output<\/a><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":"![\"\"](\"https:\/\/truelogic.org\/wordpress\/wp-content\/uploads\/2018\/03\/dict2-620x163.png\")
<\/p>\nMethods<\/h3>\n
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