Tengo by Example: Slices

Slices

Wikipedia: Array slicing
Slices are a key data type in Tengo, giving a more powerful interface to sequences than arrays.

fmt := import("fmt")

Unlike arrays, slices can be resized. A slice is often created by slicing an existing array or slice.

s := ["a", "b", "c", "d", "e"]
fmt.println("base array: ", s)

The syntax slice[low:high] creates a new slice. For example, this gets elements from index 1 to 2 (excluding 3).

l := s[1:3]
fmt.println("sl1: ", l)

This slices up to (but excluding) index 5.

l = s[:5]
fmt.println("sl2: ", l)

And this slices from index 2 (including) to the end.

l = s[2:]
fmt.println("sl3: ", l)

You can also create a copy of a slice to ensure that modifications to the new slice don't affect the original.

c := append([], s...)
fmt.println("cpy: ", c)

Slices can be composed into multi-dimensional data structures. The length of the inner slices can vary, unlike multi-dimensional arrays.

twoD := [
    [0],
    [1, 2],
    [2, 3, 4]
]
fmt.println("2d: ", twoD)

try it

base array: ["a", "b", "c", "d", "e"]
sl1: ["b", "c"]
sl2: ["a", "b", "c", "d", "e"]
sl3: ["c", "d", "e"]
cpy: ["a", "b", "c", "d", "e"]
2d: [[0], [1, 2], [2, 3, 4]]

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