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This article will explain in detail the syntax of Python data types in common collections, and the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

Set in Python data types and collection in C # are not a concept, it's a matter of translation.

The set in Python refers to the disordered and non-repetitive set of elements, which is similar to the concept of set in mathematics, which can be operated logically, such as intersection, union, difference, complement and so on.

The syntax for common collections is:

S = set (['averse,' baked,'c'])

However, set has changed a lot in Python 3.0. the syntax for creating a collection becomes: s = {1 ~ 2 ~ 3}, using curly braces, similar to dict, which will be mentioned later.

If repeating elements are passed in the set, the collection automatically merges them. This feature is very useful, such as removing a large number of repetitive elements from the list, and it is very efficient to solve the problem with set, as shown in the following example:

#-*-coding: utf-8-*-a = [11 set 22 print 33 3 4, 44 14] b = set (a) print b # output set ([33, 11, 44, 22])

For another example, find the same elements in two list (set intersection, other analogies). The code is as follows:

#-*-coding: utf-8-*-a = ["11", "22", "33"] b = ["11", "33"] c = set (a) & set (b) print c # output set (['11','33'])

Think about how you would write this algorithm if you implemented it yourself. Then you can find two larger lists, Bibi and the efficiency of the set implementation, and you will see. Use more set in the program in the future.

At present, it seems that there is no Set in the Collections of C#, but there is in C++ STL. I don't know why C# doesn't implement this interesting thing.

Dictionary (dict)

People who have used Collections in C # should be familiar with Hashtable, and the hash table in the Python data type is a dict. Like set, a dictionary is an unordered storage structure that includes keywords (key) and values corresponding to keywords (value).

What C # programmers need to know is that dict is a built-in data type in Python, defined as dictionary = {key:value}, separated by commas when there are multiple key-value pairs.

The keywords in the dictionary are immutable types, such as strings, integers, tuples containing only immutable objects, lists, and so on. A key in the dictionary can be associated with only one value, and for the same key, the added value overrides the previous value.

Anyone who has studied data structure should have an understanding of the efficiency of hash lookup in dictionaries, so I suggest using dictionaries as much as possible and not writing about the rest.

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