Python - Set Set comprehensions
Introduction
The set comprehension expression is similar in form to the list comprehension/
It is coded in curly braces instead of square brackets and runs to make a set instead of a list.
Set comprehensions run a loop and collect the result of an expression on each iteration.
A loop variable gives access to the current iteration value for use in the collection expression.
The result is a new set you create by running the code, with all the normal set behavior.
Demo
print( {x ** 2 for x in [1, 2, 3, 4]} ) # 3.X/2.7 set comprehension
Result
Here, the loop is coded on the right, and the collection expression is coded on the left (x ** 2).
The expression is saying: return a new set containing X squared, for every X in a list.
Comprehensions can iterate across other kinds of objects, such as strings.
Demo
print( {x for x in 'test'} ) # Same as: set('test') print( {c * 4 for c in 'test'} ) # Set of collected expression results print( {c * 4 for c in 'testham'} ) S = {c * 4 for c in 'test'} print( S & {'mmmm', 'xxxx'} )
Result
