Determine if a string is collapsible: Difference between revisions

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 <lang fsharp>
 // Collapse a String. Nigel Galloway: June 9th., 2020
+//As per the task description a function which 'determines if a character string is collapsible' by testing if any consecutive characters are thesame.
-let collapse n=if String.length n=0 then None else
+let isCollapsible n=n|>Seq.pairwise|>Seq.tryFind(fun(n,g)->n=g)
-                 let fN=let mutable g=n.[0] in (fun n->if n=g then false else g<-n; true)
+//As per the task description a function which 'if the string is collapsable And if so, collapses the string (by removing immediately repeated characters).
-                 let fG=n.[0..0]+System.String(n.[1..].ToCharArray()|>Array.filter fN)
+let collapse n=match isCollapsible n with
-                 if fG.Length=n.Length then None else Some fG
+                Some _->let i=Seq.head n
+                        let fN=let mutable g=i in (fun n->if n=g then false else g<-n; true)
+                        let g=System.String([|yield i;yield! Seq.tail n|>Seq.filter fN|])
+                        printfn "<<<%s>>> (length %d) colapses to <<<%s>>> (length %d)" n n.Length g g.Length
+               |     _->printfn "<<<%s>>> (length %d) does not colapse" n n.Length
+collapse ""
-let isCollapsible n=match colapse n with
+collapse "\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln "
-                     Some g->printfn "<<<%s>>> (length %d) collapses to <<<%s>>> (length %d)" n n.Length g g.Length
+collapse "..1111111111111111111111111111111111111111111111111111111111111117777888"
-                    |_->printfn "<<<%s>>> (length %d) does not collapse" n n.Length
+collapse "I never give 'em hell, I just tell the truth, and they think it's hell. "
+collapse "                                                    --- Harry S Truman  "
-isCollapsible ""
+collapse "withoutConsecutivelyRepeatedCharacters"
-isCollapsible "\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln "
-isCollapsible "..1111111111111111111111111111111111111111111111111111111111111117777888"
-isCollapsible "I never give 'em hell, I just tell the truth, and they think it's hell. "
-isCollapsible "                                                    --- Harry S Truman  "
-isCollapsible "withoutConsecutivelyRepeatedCharacters"
 </lang>
 {{out}}
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 <<<withoutConsecutivelyRepeatedCharacters>>> (length 38) does not collapse
 </pre>
 =={{header|Factor}}==
 <lang factor>USING: formatting io kernel sbufs sequences strings ;