@lang:sum

Sum the elements of an array.

Returns: number

Syntax

@lang:sum(arr)

Arguments

Name	Type	Description
arr	array	Source array

See Also

• @reduce — fold an array with any binary Operators lambda
• @map — transform each element

On-chain face (@sum!)

Sum the array return of a call into one word, on-chain: a native sumWords over the word payload. This is the fixed-operation form of @reduce!(add 0) (one on-chain loop instead of a per-element foldWords lambda call, so it is cheaper). Reach for @reduce! when you need a different reduction (min, max, bitOr, bitAnd) or a nonzero initial accumulator.

Examples

load lang

set $vault 0x44fA8E6f47987339850636F88629646662444217

# The caps sum to at least 100
assert @sum!($vault::{caps()(uint256[])}) >= 100

# Sum a mapped payload (double each element first)
def @dbl! "$x: number -> number" @num!($x * 2)
assert @sum!(@map!($vault::{caps()(uint256[])} @dbl!)) >= 200

Notes

• Arrays of single-word elements only; the result is judged as a uint word (the checked sum overflows-reverts past 2^256 - 1).
• An empty array sums to 0.
• An average is @num!(@sum!(...) / @len!(...)).

See Also

• assert, @reduce!, @len!