<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">In PHP they seem EFFECTIVELY synonymous. <span class=""><br class=""><blockquote type="cite" class="">In PHP, associative arrays are implemented as hashtables, with a bit of extra functionality.<br class=""><br class="">However technically speaking, an associative array is not identical to a hashtable - it's simply implemented in part with a hashtable behind-the-scenes. Because most of its implementation is a hashtable, it can do everything a hashtable can - but it can do more, too.<br class=""><br class="">For example, you can loop through an associative array using a for loop, which you can't do with a hashtable.<br class=""><br class="">So while they're similar, an associative array can actually do a superset of what a hashtable can do - so they're not exactly the same thing. Think of it as hashtables plus <br class=""><br class=""></blockquote></span><div class=""><div class="">From: <a href="http://stackoverflow.com/questions/3134296/hash-tables-vs-associative-arrays" class="">http://stackoverflow.com/questions/3134296/hash-tables-vs-associative-arrays</a></div><div class=""><br class=""></div><div class="">Laurie Savage</div><div class="">PVGC</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 15 Dec 2015, at 11:32 AM, Mark <<a href="mailto:mark@vceit.com" class="">mark@vceit.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_default" style="font-family:'trebuchet ms',sans-serif">Thanks, Duane. The interpretation seems to be heading in that direction, even though research is revealing that the concepts are not <i class="">perfectly</i> synonymous. In researching their differences, I found that <span style="color:rgb(34,36,38);font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;line-height:15.6px" class="">associative arrays (a.k.a. a map or dictionary) is an abstract data type (ADT) whereas a hashing table is a concrete data structure</span><span style="color:rgb(34,36,38);font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;line-height:15.6px" class="">.</span><span style="color:rgb(34,36,38);font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;line-height:15.6px" class=""> When I </span>got <a href="http://cs.stackexchange.com/questions/6678/relation-and-difference-between-associative-array-and-hashing-table" class="">this far</a> I started backing away v-e-r-y slowly...</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class="gmail_default"><br class=""></div><div class="gmail_default">"A dictionary supports Find(x) queries. For an a key x, return the element in the dictionary with key x, if such an element exists. A dynamic dictionary also supports Insert(x) and Delete(x). Common implementations of a dictionary include different kinds of balanced binary search trees (e.g. red black tree) and various kinds of hash tables.</div></blockquote><div class="gmail_default"><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class="gmail_default">In addition to Find an ADT may require support of successor(x) queries. That is, maintain a set of keys S, and given key x, find the smallest key t∈S such that s<t. Concrete data structures which support the Successor ADT include various binary search trees, and more complicated structures such as an X-fast trie or van Emde Boas tree (if the keys are integers)."</div></blockquote><div class="gmail_default"><div class=""><font color="#222426" face="trebuchet ms, sans-serif" class=""><span style="line-height:15.6px" class=""><br class=""></span></font></div><div class=""><font color="#222426" face="trebuchet ms, sans-serif" class=""><span style="line-height:15.6px" class="">Now I just have to squeeze that into a friendly slideshow...</span></font></div><div class=""><br class=""></div><div class=""><font color="#222426" face="trebuchet ms, sans-serif" class=""><span style="line-height:15.6px" class="">Cheers</span></font></div><div class=""><font color="#222426" face="trebuchet ms, sans-serif" class=""><span style="line-height:15.6px" class="">Mark</span></font></div></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On 15 December 2015 at 11:05, Collinson, Duane A <span dir="ltr" class=""><<a href="mailto:collinson.duane.a@edumail.vic.gov.au" target="_blank" class="">collinson.duane.a@edumail.vic.gov.au</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div style="direction: ltr; font-family: Tahoma; font-size: 10pt;" class=""><p class="">Hi Mark</p><div class=""> <br class="webkit-block-placeholder"></div><p class="">I interpreted this as dictionaries and hash tables are synonyms for associative arrays.</p><div class=""> <br class="webkit-block-placeholder"></div><p class="">Could see another way of teaching this KK.</p><div class=""> <br class="webkit-block-placeholder"></div><p class="">Cheers</p>
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<div style="FONT-SIZE:13px;FONT-FAMILY:Tahoma" class=""><p class=""><font color="#0000ff" class=""><em class=""><strong class="">Duane Collinson</strong></em></font></p><p class=""><em class=""><font color="#0000ff" class=""><strong class=""></strong></font></em> </p><p class=""><em class=""><font color="#0000ff" class=""><strong class="">Horsham College</strong></font></em></p><p class=""><em class=""><font color="#0000ff" class=""><strong class="">310 Baillie Street</strong></font></em></p><p class=""><em class=""><font color="#0000ff" class=""><strong class="">Horsham, Victoria 3400</strong></font></em></p><p class=""><em class=""><font color="#0000ff" class=""><strong class=""></strong></font></em> </p><p class=""><em class=""><font color="#0000ff" class=""><strong class="">(03) 5381 7100</strong></font></em></p><p class=""><em class=""><font color="#0000ff" class=""></font></em> </p><p class=""><em class=""><font color="#0000ff" class=""></font></em> </p>
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<div style="DIRECTION:ltr" class=""><font size="2" face="Tahoma" class=""><b class="">From:</b> <a href="mailto:sofdev-bounces@edulists.com.au" target="_blank" class="">sofdev-bounces@edulists.com.au</a> [<a href="mailto:sofdev-bounces@edulists.com.au" target="_blank" class="">sofdev-bounces@edulists.com.au</a>] on behalf of Mark [<a href="mailto:mark@vceit.com" target="_blank" class="">mark@vceit.com</a>]<br class="">
<b class="">Sent:</b> Tuesday, 15 December 2015 10:50 AM<br class="">
<b class="">To:</b> Year 12 Software Development Teachers' Mailing List<br class="">
<b class="">Subject:</b> [Year 12 SofDev] Reading the study design<br class="">
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<div class="gmail_default" style="FONT-SIZE:small;FONT-FAMILY:'trebuchet ms',sans-serif">
Maybe someone can help with this, or it might require Paula.</div>
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<div class="gmail_default" style="FONT-SIZE:small;FONT-FAMILY:'trebuchet ms',sans-serif">
In SD U4O1 KK2 it refers to "<span style="FONT-SIZE:10pt;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:115%" class="">uses of data structures to organise and manipulate data, including associative arrays (or dictionaries or hash tables)"</span></div>
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<span style="FONT-SIZE:10pt;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:115%" class=""><br class="">
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<span style="FONT-SIZE:10pt;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:115%" class="">I'm not sure how to interpret the 'or's after 'including'. Does it mean"</span></div>
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<span style="FONT-SIZE:10pt;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:115%" class="">- dictionaries and hash tables are synonyms for associative arrays?</span></div>
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<span style="FONT-SIZE:10pt;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:115%" class="">- we may choose between </span><span style="FONT-SIZE:13px;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:15px" class="">dictionaries and hash tables and associative arrays?</span></div>
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<span style="FONT-SIZE:13px;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:15px" class="">Neither of those makes much sense. </span></div>
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<span style="FONT-SIZE:13px;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:15px" class="">What does it mean in terms of teaching KK?</span></div>
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<span style="FONT-SIZE:13px;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:15px" class="">Regards</span></div>
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<span style="FONT-SIZE:13px;FONT-FAMILY:Calibri,sans-serif;LINE-HEIGHT:15px" class="">Mark</span></div><span class="HOEnZb"><font color="#888888" class="">
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<div class=""><span style="FONT-SIZE:12px" class="">Mark Kelly</span><br class="">
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