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Care este deosebirea dintre foldl si foldr ? - Revision history
2024-03-19T09:46:02Z
Revision history for this page on the wiki
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https://wiki.haskell.org/index.php?title=Care_este_deosebirea_dintre_foldl_si_foldr_%3F&diff=19017&oldid=prev
Ha$kell at 14:54, 10 February 2008
2008-02-10T14:54:11Z
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In priviinta valorilor ce se vor obtine dupa aplicarea lui foldl si foldr exista diferente. Ele provin din ordinea de parcurgere a listei. Fold'''l''' parcurge lista de la stanga iar fold'''r''' o parcurge de la dreapta. Evaluati: <br></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In priviinta valorilor ce se vor obtine dupa aplicarea lui foldl si foldr exista diferente. Ele provin din ordinea de parcurgere a listei. Fold'''l''' parcurge lista de la stanga iar fold'''r''' o parcurge de la dreapta. Evaluati: <br></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[http://www.cs.nott.ac.uk/~gmh/foldl.pdf A tutorial on the universality and expressiveness of fold ]- by Graham Hutton, Univ. of Nottingham, UK .</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[http://www.haskell.org/haskellwiki/Ro/Haskell <= Inapoi la pagina principala Ro/Haskell<ins class="diffchange diffchange-inline">.</ins> ]<ins class="diffchange diffchange-inline"><br> <br></ins></div></td>
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Ha$kell
https://wiki.haskell.org/index.php?title=Care_este_deosebirea_dintre_foldl_si_foldr_%3F&diff=18447&oldid=prev
Ha$kell at 17:10, 19 January 2008
2008-01-19T17:10:17Z
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>O foarte buna lucrare despre fold(r), existenta sa si implicatiile existentei sale se putea gasi aici:</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[http://www.cs.nott.ac.uk/~gmh/foldl.pdf A tutorial on the universality and expressiveness of fold ]- by Graham Hutton, Univ. of Nottingham, UK .</div></td>
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Ha$kell
https://wiki.haskell.org/index.php?title=Care_este_deosebirea_dintre_foldl_si_foldr_%3F&diff=18444&oldid=prev
Ha$kell at 16:58, 19 January 2008
2008-01-19T16:58:27Z
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Diferenta consta in ordinea in care este parcursa lista. <br></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Diferenta consta in ordinea in care este parcursa lista. <br></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Diferenta se vede mai usor atunci cand functia aplicata are proprietatea</div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Diferenta se vede mai usor atunci cand functia aplicata are proprietatea</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>de "necomutativitate a argumentelor" Adica e o functie la care schimband ordinea argumentelor se obtine (in general) alta valoare.</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>de "necomutativitate a argumentelor"<ins class="diffchange diffchange-inline">.</ins> Adica e o functie la care schimband ordinea argumentelor se obtine (in general) alta valoare.</div></td>
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Ha$kell
https://wiki.haskell.org/index.php?title=Care_este_deosebirea_dintre_foldl_si_foldr_%3F&diff=18443&oldid=prev
Ha$kell at 16:55, 19 January 2008
2008-01-19T16:55:17Z
<p></p>
<p><b>New page</b></p><div>In priviinta valorilor ce se vor obtine dupa aplicarea lui foldl si foldr exista diferente. Ele provin din ordinea de parcurgere a listei. Fold'''l''' parcurge lista de la stanga iar fold'''r''' o parcurge de la dreapta. Evaluati: <br><br />
<br />
Prelude> foldl (\ a b -> 10 * a + b) 0 [1,2] <br><br />
12 <br><br />
Prelude> foldr (\ a b -> 10 * a + b) 0 [1,2] <br><br />
30 <br><br />
Prelude> <br><br />
<br />
<br />
Diferenta consta in ordinea in care este parcursa lista. <br><br />
Diferenta se vede mai usor atunci cand functia aplicata are proprietatea<br />
de "necomutativitate a argumentelor" Adica e o functie la care schimband ordinea argumentelor se obtine (in general) alta valoare.<br />
<br />
----<br />
In priviinta '''tipurilor''' lui foldl si foldr nu este nici o diferenta: <br><br />
Prelude> :t foldl <br><br />
foldl :: '''(a -> b -> a) -> a -> [b] -> a''' <br><br />
Prelude> :t foldr <br><br />
foldr :: '''(a -> b -> b) -> b -> [a] -> b''' <br><br />
<br />
----<br />
<br />
[http://www.haskell.org/haskellwiki/Ro/Haskell <= Inapoi la pagina principala Ro/Haskell ]</div>
Ha$kell