contains

Builtin index · Collections & strings

result = contains(collection, value)

Input: collection, value · Output: result

What it is

collection is a Vec or List; value is any comparable element.

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`result = contains(collection, value)`	`collection` Vec or List`collection` is a `Vec` or `List`. `value` —`value` is any comparable element.	`result` bool	Returns a `bool`: membership test via structural equality.

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

ys = [3, 1, 4, 1, 5]
print(contains(ys, 4))     # true

print(indexof(ys, 4))      # 2

print(cumsum(ys))          # [3, 4, 8, 9, 14]

print(numel(ys))           # 5

output

true
2
[3, 4, 8, 9, 14]
5

from collections-strings

s = "  Measurement Lane  "
print("[{trim(s)}]")              # [Measurement Lane]

print(upper(trim(s)))             # MEASUREMENT LANE

print(contains(s, "Lane"))        # true

print(replace(s, "Lane", "Window"))

output

[Measurement Lane]
MEASUREMENT LANE
true
  Measurement Window

from agent-guide

figure()
polygon([0.0, 1.0, 1.0], [0.0, 0.0, 1.0], fill = "#ff0000")
savefig(tmp_svg)
print(contains(read_all_text(tmp_svg), "opacity=\"0.18\""))   # true

from agent-guide

How it works

contains(collection, value) — boolean membership test, over either a numeric Vec or a heterogeneous List (structural equality via values_equal, not the == operator, which doesn't compare Strs today — a pre-existing, separate gap).

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.