| Setting variable to false in a WHILE loop [message #175434] |
Sat, 24 September 2011 03:53  |
jwcarlton
Messages: 76
Registered: December 2010
Karma: 0
|
Member |
|
|
I'm doing a MySQL query, then running a WHILE loop on it, like so:
while (list($id, $title, $text) = mysql_fetch_row($sth)) {
if ($text) {
// do whatever
}
}
The problem that I'm having is that sometimes, it's possible for $text
to equal "" instead of NULL. I use it as a quick way to check whether
the row is new (in which case $text is NULL), or if it's been updated
(in which case $text is ""), without requiring an additional field.
I know that I could just say:
if ($text && ($text != "")) {
And I could move the list() inside of the loop, like so:
while ($row = mysql_fetch_row($sth) {
$text = false;
list($id, $title, $text) = $row;
if ($text) {
// do whatever
}
}
But I'm curious if there's a way to reset $id, $title, and $text to
false at the beginning of the loop. Something like:
// Just a mock-up, using "my" from Perl
while (my(list($id, $title, $text)) = mysql_fetch_row($sth)) {
|
|
|
|
| Re: Setting variable to false in a WHILE loop [message #175436 is a reply to message #175434] |
Sat, 24 September 2011 13:14  |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On 9/23/2011 11:53 PM, jwcarlton wrote:
> I'm doing a MySQL query, then running a WHILE loop on it, like so:
>
> while (list($id, $title, $text) = mysql_fetch_row($sth)) {
> if ($text) {
> // do whatever
> }
> }
>
> The problem that I'm having is that sometimes, it's possible for $text
> to equal "" instead of NULL. I use it as a quick way to check whether
> the row is new (in which case $text is NULL), or if it's been updated
> (in which case $text is ""), without requiring an additional field.
>
> I know that I could just say:
>
> if ($text&& ($text != "")) {
>
> And I could move the list() inside of the loop, like so:
>
> while ($row = mysql_fetch_row($sth) {
> $text = false;
> list($id, $title, $text) = $row;
>
> if ($text) {
> // do whatever
> }
> }
>
>
> But I'm curious if there's a way to reset $id, $title, and $text to
> false at the beginning of the loop. Something like:
>
> // Just a mock-up, using "my" from Perl
> while (my(list($id, $title, $text)) = mysql_fetch_row($sth)) {
>
Why complicate things? Why not just use
if ($text !== false)
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
|
|
|
|
| Re: Setting variable to false in a WHILE loop [message #175453 is a reply to message #175436] |
Wed, 28 September 2011 18:28 |
tamouse
Messages: 5
Registered: September 2011
Karma: 0
|
Junior Member |
|
|
On Saturday, September 24, 2011 8:14:46 AM UTC-5, Jerry Stuckle wrote:
> Why complicate things? Why not just use
>
> if ($text !== false)
That works, but might be a little opaque. I'd use:
if (!empty($text))
As it's a little more clear to the reader/maintainer.
Also, with the === & !== idiom, isn't it better reverse the operands, thus:
if (FALSE !== $text)
?
|
|
|
|
| Re: Setting variable to false in a WHILE loop [message #175458 is a reply to message #175453] |
Wed, 28 September 2011 19:49 |
Tim Streater
Messages: 328
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
In article
<9281403.1198.1317234500379.JavaMail.geo-discussion-forums@yqma37>,
tamouse <tamouse(dot)lists(at)gmail(dot)com> wrote:
> On Saturday, September 24, 2011 8:14:46 AM UTC-5, Jerry Stuckle wrote:
>> Why complicate things? Why not just use
>>
>> if ($text !== false)
>
> That works, but might be a little opaque. I'd use:
>
> if (!empty($text))
>
> As it's a little more clear to the reader/maintainer.
>
> Also, with the === & !== idiom, isn't it better reverse the operands, thus:
>
> if (FALSE !== $text)
This business of doing:
if (27===$myvar) ...
is the dopiest thing I ever heard of. 27 is equal to 27, end of. People
should really learn that the computer serves *them*, not the other way
around.
--
Tim
"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted" -- Bill of Rights 1689
|
|
|
|
| Re: Setting variable to false in a WHILE loop [message #175460 is a reply to message #175453] |
Thu, 29 September 2011 12:09 |
Doug Miller
Messages: 171
Registered: August 2011
Karma: 0
|
Senior Member |
|
|
On 9/28/2011 2:28 PM, tamouse wrote:
> Also, with the ===& !== idiom, isn't it better reverse the operands, thus:
>
> if (FALSE !== $text)
>
Why would you think that such a grossly counterintuitive construct is
better than the clear and obvious
if ($text !== FALSE)
?
|
|
|
|
| Re: Setting variable to false in a WHILE loop [message #175478 is a reply to message #175453] |
Sat, 01 October 2011 14:08 |
Thomas 'PointedEars'
Messages: 701
Registered: October 2010
Karma: 0
|
Senior Member |
|
|
tamouse wrote:
> On Saturday, September 24, 2011 8:14:46 AM UTC-5, Jerry Stuckle wrote:
>> Why complicate things? Why not just use
>>
>> if ($text !== false)
>
> That works, but might be a little opaque. I'd use:
>
> if (!empty($text))
>
> As it's a little more clear to the reader/maintainer.
It is not equivalent, though:
<http://php.net/empty>
> Also, with the === & !== idiom, isn't it better reverse the operands,
> thus:
>
> if (FALSE !== $text)
>
> ?
No. Why should it be?
(The PEAR Coding Standards also actively recommend against writing `false'
as `FALSE': <http://pear.php.net/manual/en/standards.naming.php>)
PointedEars
--
Anyone who slaps a 'this page is best viewed with Browser X' label on
a Web page appears to be yearning for the bad old days, before the Web,
when you had very little chance of reading a document written on another
computer, another word processor, or another network. -- Tim Berners-Lee
|
|
|
|
Calendar
Search
Help
Members
Register
Login
Home
]