AddOrdered (Stringlist function): Difference between revisions
Jump to navigation
Jump to search
m (1 revision) |
mNo edit summary |
||
| Line 16: | Line 16: | ||
==Usage notes== | ==Usage notes== | ||
<ul><li>All errors in <var>AddOrdered</var> result in request cancellation.<li><var>AddOrdered</var> always adds the indicated string, even if that string already exists on the <var>Stringlist</var>, but the new item is inserted so that the <var>Stringlist</var> is in EBCDIC order. <var>AddOrdered</var> assumes that the <var>Stringlist</var> is in EBCDIC order, so it does a pseudo binary search to locate the correct insertion point. <var>AddOrdered</var> does not validate that the <var>Stringlist</var> is in order; if it is not in order, the insertion point is unpredictable.<li>Because <var>AddOrdered</var> will insert items into the middle of a <var>Stringlist</var>, | <ul><li>All errors in <var>AddOrdered</var> result in request cancellation.<li><var>AddOrdered</var> always adds the indicated string, even if that string already exists on the <var>Stringlist</var>, but the new item is inserted so that the <var>Stringlist</var> is in EBCDIC order. <var>AddOrdered</var> assumes that the <var>Stringlist</var> is in EBCDIC order, so it does a pseudo binary search to locate the correct insertion point. <var>AddOrdered</var> does not validate that the <var>Stringlist</var> is in order; if it is not in order, the insertion point is unpredictable.<li>Because <var>AddOrdered</var> will insert items into the middle of a <var>Stringlist</var>, it is susceptible to the same page-splitting, sparse <var>Stringlist</var> leaf-page issues as the <var>Insert</var> method ([http://wiki.sirius-software.com/index.php/Insert_%28Stringlist_function%29 Insert]).</ul> | ||
==Examples== | ==Examples== | ||
| Line 22: | Line 22: | ||
<p class="code">for %i from 1 to %inlist:count | <p class="code">for %i from 1 to %inlist:count | ||
%string = %inlist:item(%i) | %string = %inlist:item(%i) | ||
%outlist:addOrdered(%string) | %outlist:addOrdered(%string) | ||
end for | end for | ||
</p> | </p> | ||
While it is generally more efficient to simply copy and sort (via the SortNew method) the input <var>Stringlist</var>, the technique above might be useful if the target <var>Stringlist</var> already has a large number of items. | While it is generally more efficient to simply copy and sort (via the <var>SortNew</var> method) the input <var>Stringlist</var>, the technique above might be useful if the target <var>Stringlist</var> already has a large number of items. | ||
[[Category:Stringlist methods|AddOrdered function]] | [[Category:Stringlist methods|AddOrdered function]] | ||
Revision as of 00:10, 25 January 2011
Add an item to an ordered Stringlist (Stringlist class)
This method adds an item to a (presumably) ordered Stringlist, inserting the item at the proper position to maintain the Stringlist's order. AddOrdered accepts one argument and returns the item number of the inserted string. AddOrdered is a callable method.
Syntax
[%number =] sl:AddOrdered( string)
Syntax terms
| %number | A numeric variable to contain the item number of the added string in the Stringlist. |
|---|---|
| sl | A Stringlist object. |
| string | A string that is to be added to the Stringlist. |
Usage notes
- All errors in AddOrdered result in request cancellation.
- AddOrdered always adds the indicated string, even if that string already exists on the Stringlist, but the new item is inserted so that the Stringlist is in EBCDIC order. AddOrdered assumes that the Stringlist is in EBCDIC order, so it does a pseudo binary search to locate the correct insertion point. AddOrdered does not validate that the Stringlist is in order; if it is not in order, the insertion point is unpredictable.
- Because AddOrdered will insert items into the middle of a Stringlist, it is susceptible to the same page-splitting, sparse Stringlist leaf-page issues as the Insert method (Insert).
Examples
The following code builds a sorted output Stringlist from an input Stringlist:
for %i from 1 to %inlist:count %string = %inlist:item(%i) %outlist:addOrdered(%string) end for
While it is generally more efficient to simply copy and sort (via the SortNew method) the input Stringlist, the technique above might be useful if the target Stringlist already has a large number of items.