August 2001
Intermediate to advanced
976 pages
38h 8m
English
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Name
IsDefined
Synopsis
IsDefined('variable_name')Determines if the specified variable exists. Returns
True if the specified variable exists or
False if it doesn’t. Note that
IsDefined( ) replaces the deprecated
ParameterExists( ) function. Examples:
<CFSET MyVar="Variable">
<CFSET Form.MyFormVar="Form Variable">
<CFOUTPUT>
<CFIF IsDefined('MyVar')>
Variable MyVar exists:<BR> MyVar = #MyVar#
<CFELSE>
No variable called MyVar exists.
</CFIF>
<P><CFIF IsDefined('MyFormVar')>
Variable MyFormVar exists:<BR> MyFormVar = #MyFormVar#
<CFELSE>
No variable called MyFormVar exists.
</CFIF>
<P><CFIF IsDefined('Queryname.field')>
Variable Queryname.Field exists:<BR> QueryName.Field = #Queryname.Field#
<CFELSE>
No variable called Queryname.Field exists.
</CFIF>
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.