fold

left-fold given collection returning accumulator

Parameters

fold collection :integer :string :dictionary :object :inline :block :range
     params :null :block
     action :block :bytecode

Attributes

with:literaluse given index
seed:anyuse specific seed value
rightperform right folding

Returns

  • :null
  • :block
  • or  :nothing

Examples

copy
fold 1..10 [x,y]-> x + y
; => 55 (1+2+3+4..)

fold 1..10 .seed:1 [x,y][ x * y ]
; => 3628800 (10!)

copy
fold 1..3 [x,y]-> x - y
; => -6

fold.right 1..3 [x,y]-> x - y
; => 2

copy
fold.seed:"0" to [:string] 1..5 [x,y] ->
    "(" ++ x ++ "+" ++ y ++ ")"
; => (((((0+1)+2)+3)+4)+5)

fold.right.seed:"0" to [:string] 1..5 [x,y] ->
    "(" ++ x ++ "+" ++ y ++ ")"
; => (1+(2+(3+(4+(5+0)))))

copy
fold 1..10 [x y z] [
    print [x y z]
    x + z - y
]
; 0 1 2
; 1 3 4
; 2 5 6
; 3 7 8
; 4 9 10
; => 5

copy
fold.with:'i 1..5 [x y][
    print [i x y]
    i * x+y
]
; 0 0 1
; 1 0 2
; 2 2 3
; 3 10 4
; 4 42 5
; => 188

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