nushell/docs/commands/reduce.md

title	layout	version
reduce	command	0.59.0

Aggregate a list table to a single value using an accumulator block.

Signature

> reduce (block) --fold --numbered

Parameters

• block: reducing function
• --fold {any}: reduce with initial value
• --numbered: iterate with an index

Examples

Sum values of a list (same as 'math sum')

> [ 1 2 3 4 ] | reduce {|it, acc| $it + $acc }

Sum values with a starting value (fold)

> [ 1 2 3 4 ] | reduce -f 10 {|it, acc| $acc + $it }

Replace selected characters in a string with 'X'

> [ i o t ] | reduce -f "Arthur, King of the Britons" {|it, acc| $acc | str find-replace -a $it "X" }

Find the longest string and its index

> [ one longest three bar ] | reduce -n { |it, acc|
        if ($it.item | str length) > ($acc | str length) {
            $it.item
        } else {
            $acc
        }
    }