Hi Rick,
I think these explanations are correct, if not someone else should
correct me :p
so, row[19] is kind of like an object and it contains the value of
whatever row[19] is.
so lets say row[19] is this <div>Hello</div>
In your 'Boolean' example, this is what is happening
If row[19] exists in the dom, print 'Yes', if not print 'No'
Now in the 'non-null' example, essentially the exact same check is
happening, but you have replaced Yes with the row[19] object, which
contains the value of Hello, so we get this
If row[19] exists in the dom, print row[19]'s value, if not print 'N/A'
So, you can see, the second example is not checking if row[19] has a
value, but whether or not it exists at all.
Now, I would take this with a pinch of salt, as my programming theory is
poor at best, but this is what I think is happening.
- Liam
Rick Faircloth wrote:
Thanks, Liam...
You'll see in my answers to my own posts that I finally figured out
the extra set of quotes was needed.
What I still don't understand is even how this logic works:
if ( row[19] ) {
row[19]
} else {
N/A
}
As a "non-null" check, it seems the statement would need to be asking:
"if there is a value at row[19], use that value...otherwise us 'N/A'"
As a Boolean check, the statement would be:
if ( row[19] == 'true' )
{ 'Yes' }
else { 'No' }
(Assuming I wrote that correctly...)
It seems the statement would be asking:
"if the value at row[19] is 'true', use 'Yes' as the output value,
otherwise, use 'No'"
In other words, how does the conditional know what's being asked in the
shorthand version?
' + (row[19] ? '' + row[19] + '' : 'N/A') + '<
That first part:
' + row[19] ? '
works the same for both value checks and Boolean checks.
How?
Rick
-----Original Message-----
From: jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com] On
Behalf Of Liam Potter
Sent: Tuesday, August 11, 2009 11:24 AM
To: jquery-en@googlegroups.com
Subject: [jQuery] Re: How to specify a default value...
Your concatenation is broke, (I'm assuming the logic behind this is
actually working)
this
>' + (row[19] ? '+ row[19] + ' : 'N/A') + '<
should be
' + (row[19] ? ''+ row[19] + '' : 'N/A') + '<
As for what is going on here, it's just an if statement shortened down,
and could be written like this
if ( row[19] ) {
row[19]
} else {
N/A
}
Rick Faircloth wrote:
Well..another unexpected result.
When the inline conditional:
' + (row[19] ? ' + row[19] + ' : 'N/A') + '<
is used when a **value is present** in row[19], I get this as the output:
+ row[19] +
instead of the actual value.
If I remove the quotes from ' + row[19] + ', I get a syntax error.
However, if **no value is present** in row[19], I get
N/A
as the output, which is expected.
So, the conditional is working if no value is present, but outputting
the literal string
+ row[19] +
if a value is not present.
Assistance in understanding, anyone?
Thanks,
Rick
*From:* jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com]
*On Behalf Of *Rick Faircloth
*Sent:* Tuesday, August 11, 2009 11:00 AM
*To:* jquery-en@googlegroups.com
*Subject:* [jQuery] Re: How to specify a default value...
Well.to answer my own question.I found this works:
out.push('<li><span class="spanLeft">Pet Deposit</span><span
class="spanRight">' + (row[19] ? ' + row[19] + ' : 'N/A') +
'</span></li>');
But how does the conditional know whether a Boolean is being checked,
as in:
' + (row[19] ? 'Yes' : 'No') + '<
Or whether the presence of a value is being checked, as in:
' + (row[19] ? ' + row[19] + ' : 'N/A') + '<
What's the logic that's occurring behind the statements to differentiate?
Thanks for any insight.
Rick
*From:* jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com]
*On Behalf Of *Rick Faircloth
*Sent:* Tuesday, August 11, 2009 10:39 AM
*To:* jquery-en@googlegroups.com
*Subject:* [jQuery] How to specify a default value...
I was shown how to use this inline condition for creating yes/no
Boolean values instead of
the normal true/false values javascript uses:
<span class="spanRight">' + (row[20] ? 'Yes' : 'No') + '</span>
I'd like to know if there's an equivalent inline method for providing
a default value
when no value is present, such as:
<span class="spanRight">' + (row[20] ? 'NORMAL ROW[20] VALUE' : 'N/A')
+ '</span>
Basically, if there's no value in the current row as position 20, then
just us 'N/A'.
Is this possible with a simple inline condition, too?
Thanks,
Rick
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