generate Command Documentation

--- title: generate categories: | generators version: 0.104.0 generators: | Generate a list of values by successively invoking a closure. usage: | Generate a list of values by successively invoking a closure. editLink: false contributors: false ---  # `generate` for [generators](/commands/categories/generators.md) <div class='command-title'>Generate a list of values by successively invoking a closure.</div> ## Signature ```> generate {flags} (closure) (initial)``` ## Parameters - `closure`: Generator function. - `initial`: Initial value. ## Input/output types: | input | output | | --------- | --------- | | list\<any\> | list\<any\> | | nothing | list\<any\> | | range | list\<any\> | | table | list\<any\> | ## Examples Generate a sequence of numbers ```nu > generate {|i| if $i <= 10 { {out: $i, next: ($i + 2)} }} 0 ╭───┬────╮ │ 0 │ 0 │ │ 1 │ 2 │ │ 2 │ 4 │ │ 3 │ 6 │ │ 4 │ 8 │ │ 5 │ 10 │ ╰───┴────╯ ``` Generate a continuous stream of Fibonacci numbers ```nu > generate {|fib| {out: $fib.0, next: [$fib.1, ($fib.0 + $fib.1)]} } [0, 1] ``` Generate a continuous stream of Fibonacci numbers, using default parameters ```nu > generate {|fib=[0, 1]| {out: $fib.0, next: [$fib.1, ($fib.0 + $fib.1)]} } ``` Generate a running sum of the inputs ```nu > 1..5 | generate {|e, sum=0| let sum = $e + $sum; {out: $sum, next: $sum} } ╭───┬────╮ │ 0 │ 1 │ │ 1 │ 3 │ │ 2 │ 6 │ │ 3 │ 10 │ │ 4 │ 15 │ ╰───┴────╯ ``` ## Notes The generator closure accepts a single argument and returns a record containing two optional keys: 'out' and 'next'. Each invocation, the 'out' value, if present, is added to the stream. If a 'next' key is present, it is used as the next argument to the closure, otherwise generation stops. Additionally, if an input stream is provided, the generator closure accepts two arguments. On each invocation an element of the input stream is provided as the first argument. The second argument is the `next` value from the last invocation. In this case, generation also stops when the input stream stops.

This document describes the `generate` command, a generator that creates a list of values by repeatedly calling a closure. The closure receives a value and returns a record with 'out' (value added to the stream) and 'next' (the next value passed to the closure) keys. The documentation includes signature, parameters, input/output types, examples, and notes on how the generator closure functions.