Forward difference: Difference between revisions
Rename Perl 6 -> Raku, alphabetize, minor clean-up
Alextretyak (talk | contribs) m (→{{header|11l}}) |
Thundergnat (talk | contribs) (Rename Perl 6 -> Raku, alphabetize, minor clean-up) |
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}
Return list
}</lang>
=={{header|AWK}}==
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(loop repeat n do (map-into list #'- (rest list) list))
(subseq list 0 (- (length list) n)))</lang>
=={{header|D}}==
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flutter: []
</pre>
=={{header|E}}==
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ok
</pre>
=={{header|F_Sharp|F#}}==▼
Straightforward recursive solution▼
<lang fsharp>let rec ForwardDifference input n =▼
match n with▼
| _ when input = [] || n < 0 -> [] // If there's no more input, just return an empty list▼
| 0 -> input // If n is zero, we're done - return the input▼
| _ -> ForwardDifference // otherwise, recursively difference..▼
(input.Tail // All but the first element▼
|> Seq.zip input // tupled with itself▼
|> Seq.map (fun (a, b) -> b-a) // Subtract the i'th element from the (i+1)'th▼
|> Seq.toList) (n-1) // Make into a list and do an n-1 difference on it</lang>▼
=={{header|Factor}}==
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test</lang>
=={{header|Fortran}}==
{{works with|Fortran|90 and later}}
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-2921
</pre>
▲=={{header|F_Sharp|F#}}==
▲Straightforward recursive solution
▲<lang fsharp>let rec ForwardDifference input n =
▲ match n with
▲ | _ when input = [] || n < 0 -> [] // If there's no more input, just return an empty list
▲ | 0 -> input // If n is zero, we're done - return the input
▲ | _ -> ForwardDifference // otherwise, recursively difference..
▲ (input.Tail // All but the first element
▲ |> Seq.zip input // tupled with itself
▲ |> Seq.map (fun (a, b) -> b-a) // Subtract the i'th element from the (i+1)'th
▲ |> Seq.toList) (n-1) // Make into a list and do an n-1 difference on it</lang>
=={{header|Go}}==
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1017 -1904
-2921</pre>
=={{header|Perl 6}}==▼
{{works with|Rakudo Star|2010-07}}▼
<p>Here we use signature matching to bind both an entire array and a version missing the head.▼
The Z- operator is a zip metaoperator with a minus to subtract the two lists pairwise.▼
It's almost a shame to define difn, since the series and subscript are hardly longer than the call itself would be, and arguably more self-documenting than the name of the function would be.▼
<lang perl6>sub dif(@array [$, *@tail]) { @tail Z- @array }▼
sub difn($array, $n) { ($array, &dif ... *)[$n] }</lang>▼
=={{header|Phix}}==
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;; -> '(-2921)
</lang>
(formerly Perl 6)
▲{{works with|Rakudo Star|2010-07}}
▲<p>Here we use signature matching to bind both an entire array and a version missing the head.
▲The Z- operator is a zip metaoperator with a minus to subtract the two lists pairwise.
▲It's almost a shame to define difn, since the series and subscript are hardly longer than the call itself would be, and arguably more self-documenting than the name of the function would be.
▲<lang perl6>sub dif(@array [$, *@tail]) { @tail Z- @array }
▲sub difn($array, $n) { ($array, &dif ... *)[$n] }</lang>
=={{header|REXX}}==
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Difference 9: -2921
</pre>
=={{header|zkl}}==
{{trans|Scheme}}
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