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Function std.range.tail

Return a range advanced to within _n elements of the end of range.

auto tail(Range) (
  Range range,
  size_t n
)
if (isInputRange!Range && !isInfinite!Range && (hasLength!Range || isForwardRange!Range));

Intended as the range equivalent of the Unix tail utility. When the length of range is less than or equal to _n, range is returned as-is.

Completes in Ο(1) steps for ranges that support slicing and have length. Completes in Ο(range.length) time for all other ranges.

Parameters

NameDescription
range range to get tail of
n maximum number of elements to include in tail

Returns

Returns the tail of range augmented with length information

Example

// tail -c n
writeln([1, 2, 3].tail(1)); // [3]
writeln([1, 2, 3].tail(2)); // [2, 3]
writeln([1, 2, 3].tail(3)); // [1, 2, 3]
writeln([1, 2, 3].tail(4)); // [1, 2, 3]
writeln([1, 2, 3].tail(0).length); // 0

// tail --lines=n
import std.algorithm.comparison : equal;
import std.algorithm.iteration : joiner;
import std.exception : assumeWontThrow;
import std.string : lineSplitter;
assert("one\ntwo\nthree"
    .lineSplitter
    .tail(2)
    .joiner("\n")
    .equal("two\nthree")
    .assumeWontThrow);

Authors

Andrei Alexandrescu, David Simcha, Jonathan M Davis, and Jack Stouffer. Credit for some of the ideas in building this module goes to Leonardo Maffi.

License

Boost License 1.0.