Swift: Iterate through array and count Ints equal to 5

Question

In Swift how would I iterate through the NSMutableArray of ints var numbers = [4,5,5,4,3] and count how many are equal to 5?

Just to remind you that var numbers = [4,5,5,4,3] is not of type NSMutableArray. Major difference is that it is a value type and not a reference to an object. Said that, I upvoted the @ Sebastian Dressler solution. — Matteo Piombo
– Matteo Piombo, Commented Jan 20, 2015 at 9:27

Sebastian · Accepted Answer · 2015-01-20 08:25:52Z

4

You can use reduce for this:

let array = [4,5,5,4,3]
let fives = array.reduce(0, combine: { $0 + Int($1 == 5) })

answered Jan 20, 2015 at 8:25

Sebastian

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5 Comments

Is this compatible with NSMutableArray?

Yes, with casting to a Swift array. Otherwise use a method profided by NSMutableArray.

That should have been "provided" ;)

I didn't know that you can use boolean literals in the constructor of Int, very classy, this should be the accepted answer.

Note that Int($1 == 5) invokes init(_ number: NSNumber) initializer defined in Foundation.

Dániel Nagy · Accepted Answer · 2015-01-20 08:22:53Z

1

One possible solution:

numbers.filter {$0 == 5}.count

answered Jan 20, 2015 at 8:22

Dániel Nagy

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Where a equals the name of the array?

Yes, it is, I just didn't described it.