std.algorithm

Module entries: all(), any(), array(), cumulativeFold(), filter(), map(), reverse(), reversed(), sort(), splitter(), zip()

all(left, right)

bool all(T, U)(T left, U right)

Returns true if all values in the range fulfill the condition.

Example:

assert((0 .. 5).all(a => a < 5));

any(left, right)

bool any(T, U)(T left, U right)

Returns true if any value in the range fulfills the condition.

Example:

assert((0 .. 5).any(a => a == 3));

array(range)

typeof(range.front)[] array(T)(T range)

Converts a range into an array.

Example:

assert((0 .. 5).array == [0, 1, 2, 3, 4]);

cumulativeFold(range, seed, lambda)

auto cumulativeFold(R, S, L)(R range, S seed, L lambda)

Applies a lambda repeatedly to an initial value and a value from a range, yielding the result at every step.

Example:

assert((1 .. 6).cumulativeFold(0, (a, b) => a + b).array == [1, 3, 6, 10, 15]);

filter(left, right)

auto filter(T, U)(T left, U right)

Filters a range by a condition.

Example:

auto a = (0 .. 10).filter(a => a > 4).array;

assert(a == [5, 6, 7, 8, 9]);

map(left, right)

auto map(T, U)(T left, U right)

Maps a range onto a lambda.

If the input range is [x, y, z], the output range is [lambda(x), lambda(y), lambda(z)].

Example:

auto a = (0 .. 5).map(a => a * 2);

assert(a.length == 5);
assert(a.array == [0, 2, 4, 6, 8]);

reverse(arr)

void reverse(T)(T[] arr)

Reverse a mutable array in place.

Example:

int mut[] array = [2, 3, 4].dup;
array.reverse;
assert(array == [4, 3, 2]);

reversed(arr)

T[] reversed(T)(T[] arr)

Given an array, return the reverse.

Example:

assert([2, 3, 4].reversed == [4, 3, 2]);

sort(array, smaller)

T sort(T, U)(T array, U smaller)

TODO: document

Example:

// quick xorshift rng
mut long a = 23;
int rand() {
    mut long x = a;
    x ^= x << 13;
    x ^= x >> 7;
    x ^= x << 17;
    a = x;
    return cast(int) x;
}
auto randomArray = [rand % i for i in 1 .. 10_000];
auto sortedArray = randomArray.sort((a, b) => a < b);
assert(sortedArray.length == randomArray.length);
// quick checksum
assert([sum a for a in randomArray] == [sum a for a in sortedArray]);
for (i in 0 .. sortedArray.length - 1) {
    assert(sortedArray[i] <= sortedArray[i + 1]);
}

splitter(range, element)

auto splitter(R, E)(R range, E element)

Given a range, returns a range of ranges consisting of the original range separated at element element.

Example:

assert([2, 3, 4, 5].splitter(4).map(a => a.array).array == [[2, 3], [5]]);

zip(first, second)

auto zip(R, S)(R first, S second)

TODO: document

Example:

assert((0 .. 5).zip(3 .. 5).array == [(0, 3), (1, 4)]);