In PureScript, how does <code>List</code> differ from <code>Array</code>? What are the reasons to use one over the other?

The representation for <code>Array</code> is a JavaScript array, whereas <code>List</code> is implemented as a cons (linked) list. <code>List</code>s have better performance characteristics when being built up item-by-item, or iterated over by taking an item from front each time - basically <code>List</code> has <code>O(1)</code> <code>cons</code> and <code>uncons</code>, vs <code>O(n)</code> for <code>Array</code>. Take a look at the documentation for <code>Array</code> and <code>List</code> on Pursuit for more information about the running time of various operations.

In PureScript, how does List differ from Array?

1 Answers

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.