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Sum and product of an array: Difference between revisions
→{{header|Raven}}: Added REBOL example.
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<lang raven>0 [ 1 2 3 ] each +
1 [ 1 2 3 ] each *</lang>
=={{header|REBOL}}==
<lang REBOL>REBOL [
Title: "Sum and Product"
Date: 2010-01-04
Author: oofoe
URL: http://rosettacode.org/wiki/Sum_and_product_of_array
]
; Simple:
sum: func [a [block!] /local x] [x: 0 forall a [x: x + a/1] x]
product: func [a [block!] /local x] [x: 1 forall a [x: x * a/1] x]
; Way too fancy:
redux: func [
"Applies an operation across an array to produce a reduced value."
a [block!] "Array to operate on."
op [word!] "Operation to perform."
/init x "Initial value (default 0)."
][if not init [x: 0] forall a [x: do compose [x (op) (a/1)]] x]
rsum: func [a [block!]][redux a '+]
rproduct: func [a [block!]][redux/init a '* 1]
; Tests:
assert: func [code][print [either do code [" ok"]["FAIL"] mold code]]
print "Simple dedicated functions:"
assert [55 = sum [1 2 3 4 5 6 7 8 9 10]]
assert [3628800 = product [1 2 3 4 5 6 7 8 9 10]]
print [crlf "Fancy reducing function:"]
assert [55 = rsum [1 2 3 4 5 6 7 8 9 10]]
assert [3628800 = rproduct [1 2 3 4 5 6 7 8 9 10]]</lang>
Output:
<pre>Simple dedicated functions:
ok [55 = sum [1 2 3 4 5 6 7 8 9 10]]
ok [3628800 = product [1 2 3 4 5 6 7 8 9 10]]
Fancy reducing function:
ok [55 = rsum [1 2 3 4 5 6 7 8 9 10]]
ok [3628800 = rproduct [1 2 3 4 5 6 7 8 9 10]]</pre>
=={{header|Ruby}}==
<lang ruby>arr = [1,2,3,4,5] # or ary = *1..5, or ary = (1..5).to_a
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