How can I truncate a String array in Swift? [duplicate]

Question

I have an array of strings in Swift that I want to shorten to only the first 5. It looks like I cannot do:

myArray = myArray[0..<5]

because I get a compiler error:

Cannot subscript a value of type [String] with an index of type Countable Range

So what can I do instead?

Show your actual code. myArray[0..<5] is legal so you don't have what you think you have; this is probably an x-y problem, and we could get to the heart of it if you showed the real code. — matt
– matt, Commented Aug 9, 2017 at 17:38
while myArray[0..<5] may be legal, array.prefix(n) is a safer way since it is bounds safe! — Moriarty
– Moriarty, Commented Aug 9, 2017 at 17:48

matt · Accepted Answer · 2017-08-09 17:41:10Z

10

I would say

let arr2 = arr1.prefix(5)

Keep in mind that the result is a Slice. If you want an array, coerce back to an array. So e.g.

var arr1 = // ...
arr1 = Array(arr1.prefix(5))

However, the notation arr1[0..<5] is legal, though with the same proviso: it's a slice and would need to be cast back to an array in order to assign it where an array is expected.

edited Aug 9, 2017 at 17:41

answered Aug 9, 2017 at 17:35

matt

540k97 gold badges944 silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Moriarty · Accepted Answer · 2017-08-09 17:37:08Z

4

array = [1,2,3,4,5,6]
n = 5
array.prefix(n)

answered Aug 9, 2017 at 17:37

Moriarty

5356 silver badges20 bronze badges

Collectives™ on Stack Overflow

How can I truncate a String array in Swift? [duplicate]

2 Answers 2

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Linked

Related