ORDER Function

M言語プログラミングブック [WALTERS1997] から引用

Page 134-148.

$ORDER

The order function allows you to traverse some or all of a global. The $order function operates on a single subscript level within a global, and returns the next subscript value in collating sequence that exists at that level in the global. You can specify some starting value, and the $order function will find the next value that exists in collating sequence. To find the first subscript at the specified level, use a starting value of null (“”). To find the first subscript at the specified level that starts with “C”, use a starting value that collates just before “C”, for example “B~”

Example:

>zwrite lcl(1)=3 lcl(“x”)=4 GTM>write $order(lcl(“”)) 1 This example returns the first node, that is 1, because the specified last subscript of the argument is null and lcl has no null subscript.

Example:

>write $order(lcl(1)) x This example returns the first node after lcl(1) that is x because lcl has no null subscript.

Example:

>write $order(lcl(“”),-1) x This example returns the last node that is, x, because the last subscript of the first argument is null and second argument is -1.

Previous topic

LENGTH Function

Next topic

PIECE Function

This Page

inserted by FC2 system