dude, binary search algorithms are pretty easy to implement. They just
sound like they are fancy...
Im sure there was psuedo code for it in my y12 computer studies text book.
For simple array searches its proly the fastest search you will need.
ie. its an O(logn) operation. There are faster searches, but you wont
notice the difference on small arrays that much.
99.9% of comp sci students would have to write this algorithm at some
stage of their course.
ps. source code below is off the top of my head, might have to debug if
you are going to copy / paste.
<cfscript>
function binarySearch(sortedArray, startIdx, endIdx, value)
{
arrayMid = endIdx / 2;
if( sortedArray[arrayMid] EQ value) //found the value
return arrayMid;
else if ( sortedArray[arrayMid] GT value) //search left
binarySearch(sortedArray, startIdx, arrayMid-1, value);
else if ( sortedArray[arrayMid] LT value) //search right
binarySearch(sortedArray, arrayMid+1, endIdx, value);
else if ( startIdx > endIdx ) //value not found.
return -1;
}
sortedArray = ArraySort(unsoredArray);
result = binarySearch(sortedArray, 1, ArrayLen(sortedArray), value);
</cfscript>
Pat
ps. before you dig into a 3d array. think if an array of structs might
work for you better. i dont know the problem, but values like name,type
sound like it could be a candidate for an array of structs.
Chad Renando wrote:
Thanks Mark...
"quite easily write yourself a quick binary search algorithm"
you make me chuckle... *chuckle* I'll get to that right after I whip
up my CFC for splitting atoms.
I'll have a look at the java thing.
Are array's overly bursonsome? I am putting all my form field
attributes (name, type, etc) in an array, which will likely end up
being 3-dimensions. The information in the array is coming from 3 or
4 queries, so either I loop through the queries in the body of the
page (I think kinda messy) or loop through my single array. I am not
adding any looping to create the array.
Cheers,
Chad
who thinks he used up his sigs for the day
On 6/3/05, Mark Mandel <[EMAIL PROTECTED]> wrote:
Is the array sorted in any way?
If it's completely un-sorted, you kinda don't have any options but to
do a O(n) search.
If it is sorted, you could quite easily write yourself a quick binary
search algorithm, while it isn't the fastest searcher in the world, it
is better than looping through all the items.
OR you could just be really lazy, and utilise the contains() Java
function off the myArray.
http://java.sun.com/j2se/1.4.2/docs/api/java/util/Vector.html#contains(java.lang.Object)
Could be lots of fun since it's a 2d array.
You may want to look into alternative data structures for your data if
it's a 2d array and you are finding it hard to manage.
No reason at all you can't leverage Java Collections.
Mark
On 6/3/05, Chad Renando <[EMAIL PROTECTED]> wrote:
'morning all.
What would be the best way to find a particular value in an array?
Ideally, I would like to query my array to get a certain value where a
condition is true, sort of like
SELECT MyArray[1][5]
FROM MyArray
WHERE MyArray[1][2] = "Something"
The altrnative is to loop through the array and grab the value on the
way through, but I am thinking I will take a performance hit,
particularly as I am doing this within a loop already...
<cfloop index="i" from="1" to="#ArrayLen(MyArray)#">
<cfif MyArray[1][2] = "Something"><cfset MyValue=1></cfif>
</cfloop>
Cheers,
Chad
who uses band names like Rammstein in general conversation 'cause it
just sounds cool
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