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std.algorithm.setops.SetDifference/setDifference - multiple declarations

Function setDifference

Lazily computes the difference of r1 and r2. The two ranges are assumed to be sorted by less. The element types of the two ranges must have a common type.

SetDifference!(less,R1,R2) setDifference(alias less, R1, R2) (
  R1 r1,
  R2 r2
);

In the case of multisets, considering that element a appears x times in r1 and y times and r2, the number of occurences of a in the resulting range is going to be x-y if x > y or 0 othwerise.

Parameters

NameDescription
less Predicate the given ranges are sorted by.
r1 The first range.
r2 The range to subtract from r1.

Returns

A range of the difference of r1 and r2.

See also

setSymmetricDifference

Example

import std.algorithm.comparison : equal;
import std.range.primitives : isForwardRange;

//sets
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
assert(equal(setDifference(a, b), [5, 9]));
static assert(isForwardRange!(typeof(setDifference(a, b))));

// multisets
int[] x = [1, 1, 1, 2, 3];
int[] y = [1, 1, 2, 4, 5];
auto r = setDifference(x, y);
assert(equal(r, [1, 3]));
assert(setDifference(r, x).empty);

Struct SetDifference

Lazily computes the difference of r1 and r2. The two ranges are assumed to be sorted by less. The element types of the two ranges must have a common type.

struct SetDifference(alias less, R1, R2)
  
if (isInputRange!R1 && isInputRange!R2);

In the case of multisets, considering that element a appears x times in r1 and y times and r2, the number of occurences of a in the resulting range is going to be x-y if x > y or 0 othwerise.

Constructors

NameDescription
this

Properties

NameTypeDescription
empty[get] bool
front[get] auto
save[get] typeof(this)

Methods

NameDescription
popFront

Parameters

NameDescription
less Predicate the given ranges are sorted by.
r1 The first range.
r2 The range to subtract from r1.

Returns

A range of the difference of r1 and r2.

See also

setSymmetricDifference

Example

import std.algorithm.comparison : equal;
import std.range.primitives : isForwardRange;

//sets
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
assert(equal(setDifference(a, b), [5, 9]));
static assert(isForwardRange!(typeof(setDifference(a, b))));

// multisets
int[] x = [1, 1, 1, 2, 3];
int[] y = [1, 1, 2, 4, 5];
auto r = setDifference(x, y);
assert(equal(r, [1, 3]));
assert(setDifference(r, x).empty);

Authors

Andrei Alexandrescu

License

Boost License 1.0.