In PureScript, how does List differ from Array?
What are the reasons to use one over the other?
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1 Answer
The representation for Array is a JavaScript array, whereas List is implemented as a cons (linked) list.
Lists have better performance characteristics when being built up item-by-item, or iterated over by taking an item from front each time - basically List has O(1) cons and uncons, vs O(n) for Array.
Take a look at the documentation for Array and List on Pursuit for more information about the running time of various operations.
3 Comments
babelchips
It is worth noting that the List notation in Purescript (for example
[1,2,3]) produces an Array of the given type and not a List.
kishlaya
To add further,
1 : 2 : 3 : Nil will give you the required List of elements [1,2,3]
Fernando Basso
Also,
import Data.List (range) then range 1 3 also produces (1 : 2 : 3 : Nil), which is a list, and not an array.