Question

#11

On 9/26/2011 4:39 PM, Bint wrote:

[snip[

Quote:

I just cannot believe that

if ($string)

does not give the same result as

if ($string != 0)

That is a failing of your belief system, not of the language design.
There is no reason to expect that comparing a string to a numeric value
will produce a meaningful result.

#12

On Mon, 26 Sep 2011 11:08:53 -0500, Bint wrote:

Quote:

Hi,

Can someone tell me why this little piece of php/mysql code fails?

$row = $result->fetch_assoc();

if ($clog)
fwrite($logfile,"row['nametag'] {$row['nametag']}\n");

if ($row['nametag'] != 0) {
if ($clog)
fwrite($logfile,"name {$row['nametag']}\n");
}

I've got this logfile where I am putting debug output. In the above, the
first fwrite works -- it writes the name contained in the row value
'nametag'.

But then, when I test that same value for nonzero, it fails? If never
prints that second line. Why should $row['nametag'] fail the != 0 test?

Thanks
Bob

Simple. You're trying to check to see if a string value is a numeric zero or not. That ain't gonna happen.
For instance
if ($a)=1 do this.
What you need to do is to test for NULL. That is, the string has no content.
BASIC would use something like if a$<>"" then dothis.
Or if len(a$)<1 then do this. len=length
Which, IMO is more proper since a string of 1 character could have a value of zero.

If you are attempting to test for the string value to be not zero, then you must convert the string to a numeric value and check that result.

If my line wrap is screwed up, that's because I hit some keys I should not have.

#13

richard:

Quote:

Simple. You're trying to check to see if a string value is a numeric
zero or not. That ain't gonna happen. For instance
if ($a)=1 do this.

'This' will be done, because now, you assign value 1 to $a successfully.

Quote:

What you need to do is to test for NULL.

In PHP? That would be isset($a), which returns true for an empty string.

Quote:

That is, the string has no
content. BASIC would use something like if a$<>"" then dothis.

An empty string is not equivalent to NULL.

Quote:

If my line wrap is screwed up, that's because I hit some keys I
should not have.

The line wrap is OK, but your comments aren't 100% correct.

--
Erick

#14

On 27.09.2011 09:21, Erick T. Barkhuis wrote:

Quote:

if ($a)=1 do this.

'This' will be done, because now, you assign value 1 to $a successfully.
Nope. That is syntax error. Parentheses make this a value, not a variable.

#15

Jacek Krysztofik:

Quote:

On 27.09.2011 09:21, Erick T. Barkhuis wrote:
if ($a)=1 do this.

'This' will be done, because now, you assign value 1 to $a
successfully.
Nope. That is syntax error. Parentheses make this a value, not a
variable.

Ah well, I considered that a typo, and thought that
if ($a=1)
was meant.

--
Erick

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Re: Question - 09-26-2011 , 09:32 PM

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