reduce for filters
Aggregate a list to a single value using an accumulator closure.
Signature
> reduce (closure) --fold
Parameters
closure: reducing function--fold {any}: reduce with initial value
Input/output types:
| input | output |
|---|---|
| list<any> | any |
| range | any |
| table | any |
Examples
Sum values of a list (same as 'math sum')
> [ 1 2 3 4 ] | reduce {|it, acc| $it + $acc }
10
Sum values of a list, plus their indexes
> [ 8 7 6 ] | enumerate | reduce -f 0 {|it, acc| $acc + $it.item + $it.index }
24
Sum values with a starting value (fold)
> [ 1 2 3 4 ] | reduce -f 10 {|it, acc| $acc + $it }
20
Replace selected characters in a string with 'X'
> [ i o t ] | reduce -f "Arthur, King of the Britons" {|it, acc| $acc | str replace -a $it "X" }
ArXhur, KXng Xf Xhe BrXXXns
Add ascending numbers to each of the filenames, and join with semicolons.
> ['foo.gz', 'bar.gz', 'baz.gz'] | enumerate | reduce -f '' {|str all| $"($all)(if $str.index != 0 {'; '})($str.index + 1)-($str.item)" }
1-foo.gz; 2-bar.gz; 3-baz.gz
Concatenate a string with itself, using a range to determine the number of times.
> let s = "Str"; 0..2 | reduce -f '' {|it, acc| $acc + $s}
StrStrStr