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itemtoindex [2006/08/01 03:45] (current)
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 +# $EPIC: itemtoindex.txt,​v 1.2 2006/08/01 03:40:36 sthalik Exp $
 +======Synopsis:​======
 +$indextoitem(<​array>​ <index number>) \\
 +$itemtoindex(<​array>​ <item number>)
 +
 +======Technical:​======
 +These functions are used to convert between array item numbers are index
 +numbers.
 +
 +Item numbers are counted incrementally as items are added to an array,
 +starting at 0 (zero). ​ Each new item uses the next available item number;
 +if there are 5 items in an array, the next item that may be added is item
 +number 5 (remember that we count from zero... 5 items is 0..4).
 +
 +Index numbers represent each items position in the array when sorted.
 +Items are sorted based on their ascii values. ​ This is generally
 +alphabetical;​ however, since it is based on ascii values, all capital
 +letters are sorted after all lowercase letters. ​ It follows a sorting
 +algorithm similar to the $[[sort]]() function'​s.
 +
 +======Practical:​======
 +The $__indextoitem__() function converts an index number in the given array
 +to its corresponding item number; $__itemtoindex__() does just the opposite.
 +This is mostly useful in conjunction with $[[igetitem]]() or $[[ifinditem]](),​
 +allowing an array to be dealt with in a logical order.
 +
 +======Returns:​======
 +<​file>​
 +  -2   ​cannot find index/item number in array
 +  -1   ​cannot find named array
 +> -1   item number corresponding to given index number (and vice verse)
 +</​file>​
 +
 +======Examples:​======
 +<​file>​
 +$setitem(booya 0 hello)
 +$setitem(booya 1 goodbye)
 +$itemtoindex(booya 0)                 ​returns 1
 +$indextoitem(booya 1)                 ​returns 0
 +$itemtoindex(foobar 0)                returns -1
 +$itemtoindex(booya 100)               ​returns -2
 +</​file>​
  
itemtoindex.txt ยท Last modified: 2006/08/01 03:45 (external edit)