slice

slice <iterable> <start> [end]

A bounded sub-range of an iterable, as a new iterable.

slice takes two or three arguments. With a start only, it yields every element from that index onward; with a start and an end, it yields the elements at indices start up to but not including end.

Arguments

• <iterable> — a list or any iterable. A bare string is not iterable; convert it first with words.
• <start> — an int, the 0-based index of the first element to keep. A negative start is treated as 0.
• [end] — an optional int, the 0-based index to stop before. When omitted, the slice is unbounded and runs to the end of the iterable. A start/end pair that selects nothing (for example end not past start) produces an empty slice.

Returns

An iterable over the selected elements. Consume it with each, count, first, or another iterable consumer.

Examples

after command (say) {
  do "say middle = [count [slice [words "a b c d e"] 1 3]]"
}

slice ... 1 3 keeps the elements at indices 1 and 2 ("b" and "c"), so [count ...] evaluates to 2 and the mob says "middle = 2."

after command (say) {
  each [slice [words "a b c d e"] 2] { <w>
    do "say tail word $w"
  }
}

With no end, the slice runs from index 2 to the end — "c", "d", and "e" — and the mob says one line per word. (Counting that same slice gives 3.)

See also

• nth — a single element by index instead of a range.
• select — keep elements by a predicate rather than position.
• count, first, each — consume the resulting iterable.
• Iterables and iterables · Types