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version 2.109.0

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Function std.algorithm.searching.minElement

Iterates the passed range and returns the minimal element. A custom mapping function can be passed to map. In other languages this is sometimes called argmin.

auto minElement(alias map, Range) (
  Range r
)
if (isInputRange!Range && !isInfinite!Range);

auto minElement(alias map, Range, RangeElementType) (
  Range r,
  RangeElementType seed
)
if (isInputRange!Range && !isInfinite!Range && !is(CommonType!(ElementType!Range, RangeElementType) == void));

Complexity

O(n) Exactly n - 1 comparisons are needed.

Parameters

NameDescription
map custom accessor for the comparison key
r range from which the minimal element will be selected
seed custom seed to use as initial element

Precondition

If a seed is not given, r must not be empty.

Returns

The minimal element of the passed-in range.

Note

If at least one of the arguments is NaN, the result is an unspecified value.

If you want to ignore NaNs, you can use filter and std.math.isNaN to remove them, before applying minElement. Add a suitable seed, to avoid error messages if all elements are NaNs: 

<range>.filter!(a=>!a.isNaN).minElement(<seed>);

If you want to get NaN as a result if a NaN is present in the range, you can use fold and std.math.isNaN: 

<range>.fold!((a,b)=>a.isNaN || b.isNaN ? real.nan : a < b ? a : b);

See Also

maxElement, min, minCount, minIndex, minPos

Example

import std.range : enumerate;
import std.typecons : tuple;

writeln([2, 7, 1, 3].minElement); // 1

// allows to get the index of an element too
writeln([5, 3, 7, 9].enumerate.minElement!"a.value"); // tuple(1, 3)

// any custom accessor can be passed
writeln([[0, 4], [1, 2]].minElement!"a[1]"); // [1, 2]

// can be seeded
int[] arr;
writeln(arr.minElement(1)); // 1

Authors

Andrei Alexandrescu

License

Boost License 1.0.