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39 lines
964 B
Markdown
39 lines
964 B
Markdown
# reduce
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Aggregate a list table to a single value using an accumulator block.
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Block must be (A, A) -> A unless --fold is selected, in which case it may be A, B -> A.
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## Usage
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```shell
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> reduce <block> {flags}
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```
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## Parameters
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* `<block>` reducing function
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## Flags
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* -h, --help: Display this help message
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* -f, --fold <any>: reduce with initial value
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* -n, --numbered: returned a numbered item ($it.index and $it.item)
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## Examples
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Simple summation (equivalent to math sum)
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```shell
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> echo 1 2 3 4 | reduce { $acc + $it }
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```
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Summation from starting value using fold
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```shell
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> echo 1 2 3 4 | reduce -f (-1) { $acc + $it }
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```
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Folding with rows
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```shell
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> <table> | reduce -f 1.6 { $acc * (echo $it.a | str to-int) + (echo $it.b | str to-int) }
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```
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Numbered reduce to find index of longest word
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```shell
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> echo one longest three bar | reduce -n { if ($it.item | str length) > ($acc.item | str length) {echo $it} {echo $acc}} | get index
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```
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