Lambda

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Available on all platforms

The Lambda class is a collection of methods to support functional programming. It is ideally used with using Lambda and then acts as an extension to Iterable types.

On static platforms, working with the Iterable structure might be slower than performing the operations directly on known types, such as Array and List.

If the first argument to any of the methods is null, the result is unspecified.

See also:

• https://haxe.org/manual/std-Lambda.html

Static methods

staticarray<A>(it:Iterable<A>):Array<A>

Creates an Array from Iterable it.

If it is an Array, this function returns a copy of it.

staticconcat<T>(a:Iterable<T>, b:Iterable<T>):Array<T>

Returns a new Array containing all elements of Iterable a followed by all elements of Iterable b.

If a or b are null, the result is unspecified.

staticcount<A>(it:Iterable<A>, ?pred:(item:A) ‑> Bool):Int

Returns the number of elements in it for which pred is true, or the total number of elements in it if pred is null.

This function traverses all elements.

staticempty<T>(it:Iterable<T>):Bool

Tells if Iterable it does not contain any element.

staticexists<A>(it:Iterable<A>, f:(item:A) ‑> Bool):Bool

Tells if it contains an element for which f is true.

This function returns true as soon as an element is found for which a call to f returns true.

If no such element is found, the result is false.

If f is null, the result is unspecified.

staticfilter<A>(it:Iterable<A>, f:(item:A) ‑> Bool):Array<A>

Returns a Array containing those elements of it for which f returned true. If it is empty, the result is the empty Array even if f is null. Otherwise if f is null, the result is unspecified.

staticfind<T>(it:Iterable<T>, f:(item:T) ‑> Bool):Null<T>

Returns the first element of it for which f is true.

This function returns as soon as an element is found for which a call to f returns true.

If no such element is found, the result is null.

If f is null, the result is unspecified.

staticfindIndex<T>(it:Iterable<T>, f:(item:T) ‑> Bool):Int

Returns the index of the first element of it for which f is true.

This function returns as soon as an element is found for which a call to f returns true.

If no such element is found, the result is -1.

If f is null, the result is unspecified.

staticinlineflatMap<A, B>(it:Iterable<A>, f:(item:A) ‑> Iterable<B>):Array<B>

A composition of map and flatten. The order of elements is preserved. If f is null, the result is unspecified.

staticinlineflatten<A>(it:Iterable<Iterable<A>>):Array<A>

Concatenate a list of iterables. The order of elements is preserved.

staticfold<A, B>(it:Iterable<A>, f:(item:A, result:B) ‑> B, first:B):B

Functional fold on Iterable it, using function f with start argument first.

If it has no elements, the result is first.

Otherwise the first element of it is passed to f alongside first. The result of that call is then passed to f with the next element of it, and so on until it has no more elements.

If it or f are null, the result is unspecified.

staticfoldi<A, B>(it:Iterable<A>, f:(item:A, result:B, index:Int) ‑> B, first:B):B

Similar to fold, but also passes the index of each element to f.

If it or f are null, the result is unspecified.

staticforeach<A>(it:Iterable<A>, f:(item:A) ‑> Bool):Bool

Tells if f is true for all elements of it.

This function returns false as soon as an element is found for which a call to f returns false.

If no such element is found, the result is true.

In particular, this function always returns true if it is empty.

If f is null, the result is unspecified.

statichas<A>(it:Iterable<A>, elt:A):Bool

Tells if it contains elt.

This function returns true as soon as an element is found which is equal to elt according to the == operator.

If no such element is found, the result is false.

staticindexOf<T>(it:Iterable<T>, v:T):Int

Returns the index of the first element v within Iterable it.

This function uses operator == to check for equality.

If v does not exist in it, the result is -1.

staticiter<A>(it:Iterable<A>, f:(item:A) ‑> Void):Void

Calls f on all elements of it, in order.

If f is null, the result is unspecified.

staticlist<A>(it:Iterable<A>):List<A>

Creates a List form Iterable it.

If it is a List, this function returns a copy of it.

staticinlinemap<A, B>(it:Iterable<A>, f:(item:A) ‑> B):Array<B>

Creates a new Array by applying function f to all elements of it. The order of elements is preserved. If f is null, the result is unspecified.

staticinlinemapi<A, B>(it:Iterable<A>, f:(index:Int, item:A) ‑> B):Array<B>

Similar to map, but also passes the index of each element to f. The order of elements is preserved. If f is null, the result is unspecified.