Max and min in an array of Float in Swift

Question

According to this answer, to obtain the maximum of an array we can do:

let nums = [1, 6, 3, 9, 4, 6];
let numMax = nums.reduce(Int.min, { max($0, $1) })

How can we do the same for an Array<Float>, since there's no min and max for Float?

let floats: Array<Float> = [2.45, 7.21, 1.35, 10.22, 2.45, 3];

score 8 · Accepted Answer · edited May 23 '17 at 12:33

The solution given here https://stackoverflow.com/a/24161004/1187415 works for for all sequences of comparable elements, therefore also for an array of floats:

let floats: Array<Float> = [2.45, 7.21, 1.35, 10.22, 2.45, 3]
let numMax = maxElement(floats)

maxElement() is defined in the Swift library as

/// Returns the maximum element in `elements`.  Requires:
/// `elements` is non-empty. O(countElements(elements))
func maxElement<R : SequenceType where R.Generator.Element : Comparable>(elements: R) -> R.Generator.Element

score 6 · Answer 2 · answered Oct 27 '14 at 11:32

6

Just use the first array element as the initial value:

let numMax = floats.reduce(floats[0], { max($0, $1) })

but of course you need to check that the floats array is not empty before doing it.

answered Oct 27 '14 at 11:32

Antonio

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codester · Answer 3 · 2014-10-27T11:57:29.337

3

You can use -FLT_MAX which returns minimum magnitude of Float and used for same purpose

let numMax = floats.reduce(-FLT_MAX, { max($0, $1) })

For Double array you can use -DBL_MAX

If you want maximum magnitude value of Float use FLT_MAX.FLT_MIN is Minimum representable postive floating-point number.

edited Oct 27 '14 at 11:57

answered Oct 27 '14 at 11:31

codester

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Thanks, I wasn't aware of `FLT_MIN`. – gpbl Oct 27 '14 at 11:42
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It should be `-FLT_MAX` that for minimum magnitude value for `Float`.FLT_MIN gives minimum vale of exponent.So i am changing my answer – codester Oct 27 '14 at 11:50
Where can I find the documentation of those variables? – gpbl Oct 27 '14 at 11:51

score 2 · Answer 4 · answered Mar 11 '19 at 19:43

2

Swift 4 has a .max() method for Array<Float>.

Example:

let floats: Array<Float> = [2.45, 7.21, 1.35, 10.22, 2.45, 3]
let max = floats.max()

Note: max() returns an optional so there's a chance it could come back nil.

answered Mar 11 '19 at 19:43

NFarrell

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score 1 · Answer 5 · answered Dec 25 '15 at 08:15

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Swift 2:

var graphPoints:[Int] = [4, 2, 6, 4, 5, 8, 3]
let maxValue = graphPoints.maxElement()

answered Dec 25 '15 at 08:15

William Hu

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score 0 · Answer 6 · answered Jun 23 '21 at 08:03

0

Tested in Swift >= 5.0

let numbers = [12.9, 2.7, 3.7, 4, 5, 4, 12.8]
print(numbers.max() ?? 0) // Output 12.9
print(numbers.min() ?? 0) // Output 2.7

answered Jun 23 '21 at 08:03

emraz

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Max and min in an array of Float in Swift

6 Answers6