Julia's array comprehensions use the following syntax:
[expression for element = iterable]
Note that as with for
loops, all of =
, in
, and ∈
are accepted for the comprehension.
This is roughly equivalent to creating an empty array and using a for
loop to push!
items to it.
result = []
for element in iterable
push!(result, expression)
end
however, the type of an array comprehension is as narrow as possible, which is better for performance.
For example, to get an array of the squares of the integers from 1
to 10
, the following code may be used.
squares = [x^2 for x=1:10]
This is a clean, concise replacement for the longer for
-loop version.
squares = []
for x in 1:10
push!(squares, x^2)
end