Set

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Syntax

Remarks

Sets are unordered and have very fast lookup time (amortized O(1) if you want to get technical). It is great to use when you have a collection of things, the order doesn’t matter, and you’ll be looking up items by name a lot. If it makes more sense to look up items by an index number, consider using a list instead. If order matters, consider a list as well.

Sets are mutable and thus cannot be hashed, so you cannot use them as dictionary keys or put them in other sets, or anywhere else that requires hashable types. In such cases, you can use an immutable frozenset.

The elements of a set must be hashable. This means that they have a correct __hash__ method, that is consistent with __eq__. In general, mutable types such as list or set are not hashable and cannot be put in a set. If you encounter this problem, consider using dict and immutable keys.

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Set:
* Set

Table Of Contents
2 Filter
3 List
7 Loops
22 Reduce
27 Classes
31 Set
42 Tuple
45 Enum
62 Sockets
89 urllib
92 Idioms
104 Stack
105 Profiling
109 Logging
111 os module
118 Mixins
120 ArcPy
126 Arrays
132 2to3 tool
135 Unicode
138 Neo4j
140 Curses
141 Templates
145 heapq
146 tkinter
154 Audio
155 pyglet
157 ijson
160 Flask
161 Groupby
163 pygame
165 hashlib
166 Gzip
167 ctypes
185 pyaudio
186 shelve