20 lines
423 B
Plaintext
20 lines
423 B
Plaintext
;; rem : the foldX family always need an initial value
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;; fold left a list
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(foldl + 0 (iota 10)) ;; 0 + 1 + .. + 9
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→ 45
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;; fold left a sequence
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(lib 'sequences)
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(foldl * 1 [ 1 .. 10])
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→ 362880 ;; 10!
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;; folding left and right
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(foldl / 1 ' ( 1 2 3 4))
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→ 8/3
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(foldr / 1 '(1 2 3 4))
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→ 3/8
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;;scanl gives the list (or sequence) of intermediate values :
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(scanl * 1 '( 1 2 3 4 5))
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→ (1 1 2 6 24 120)
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