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preg_match(): return vualue

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  preg_match(): return vualue alex <1j9448a02@lnx159sneakemail.com.invalid> - 2020-11-28 09:40 +0100
    Re: preg_match(): return vualue Stefan+Usenet@Froehlich.Priv.at (Stefan Froehlich) - 2020-11-28 08:46 +0000
      Re: preg_match(): return vualue alex <1j9448a02@lnx159sneakemail.com.invalid> - 2020-11-28 15:09 +0100
        Re: preg_match(): return vualue Allodoxaphobia <trepidation@example.net> - 2020-11-28 18:12 +0000
    Re: preg_match(): return vualue "J.O. Aho" <user@example.net> - 2020-11-28 10:57 +0100
      Re: preg_match(): return vualue alex <1j9448a02@lnx159sneakemail.com.invalid> - 2020-11-28 15:09 +0100

#18428 — preg_match(): return vualue

 From https://www.php.net/manual/en/function.preg-match.php
Warning  This function may return Boolean FALSE, but may also return a 
non-Boolean value which evaluates to FALSE. Please read the section on 
Booleans for more information. Use the === operator for testing the 
return value of this function.

That is?

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#18429

On Sat, 28 Nov 2020 09:40:27 alex wrote:
> From https://www.php.net/manual/en/function.preg-match.php
> Warning  This function may return Boolean FALSE, but may also return a 
> non-Boolean value which evaluates to FALSE. Please read the section on 
> Booleans for more information. Use the === operator for testing the 
> return value of this function.
> 
> That is?

Immediately above the quoted paragraph:

#v+
preg_match() returns 1 if the pattern matches given subject, 0 if it
does not, or FALSE if an error occurred
#v-

A test for (preg_match(...) == 0) will succeed if the match fails OR
if an error occurs.

Bye,
Stefan

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#18431

Il 28/11/20 09:46, Stefan Froehlich ha scritto:
> Immediately above the quoted paragraph:
> 
> #v+
> preg_match() returns 1 if the pattern matches given subject, 0 if it
> does not, or FALSE if an error occurred
> #v-
> 
> A test for (preg_match(...) == 0) will succeed if the match fails OR
> if an error occurs.

However, the documentation is not easy to understand.

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#18433

On Sat, 28 Nov 2020 15:09:12 +0100, alex wrote:
> Il 28/11/20 09:46, Stefan Froehlich ha scritto:
>> Immediately above the quoted paragraph:
>> 
>> #v+
>> preg_match() returns 1 if the pattern matches given subject, 0 if it
>> does not, or FALSE if an error occurred
>> #v-
>> 
>> A test for (preg_match(...) == 0) will succeed if the match fails OR
>> if an error occurs.
>
> However, the documentation is not easy to understand.

heh...  Documentation rarely is.  :-)

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#18430

On 28/11/2020 09.40, alex wrote:
>  From https://www.php.net/manual/en/function.preg-match.php
> Warning  This function may return Boolean FALSE, but may also return a 
> non-Boolean value which evaluates to FALSE. Please read the section on 
> Booleans for more information. Use the === operator for testing the 
> return value of this function.
> 
> That is?

Put is simply you can get a result that is 0 (no result) or false 
(error), these two values are equal if you make a simple comparison of 
the values

var_dump(0 == false); // => bool(true)

If you need to distinguish between error and no result you need to see 
if the values are identical

var_dump(0 === false); // => bool(false)


In theory the error result could happen when you have a string that 
should match what you are looking for, but also include data that causes 
the regex to fail.

See https://www.php.net/manual/en/language.operators.comparison.php for 
more information on comparison operators.

-- 

  //Aho

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#18432

Il 28/11/20 10:57, J.O. Aho ha scritto:
> 
> Put is simply you can get a result that is 0 (no result) or false 
> (error), these two values are equal if you make a simple comparison of 
> the values
> 
> var_dump(0 == false); // => bool(true)
> 
> If you need to distinguish between error and no result you need to see 
> if the values are identical
> 
> var_dump(0 === false); // => bool(false)
> 
> 
> In theory the error result could happen when you have a string that 
> should match what you are looking for, but also include data that causes 
> the regex to fail.
> 
> See https://www.php.net/manual/en/language.operators.comparison.php for 
> more information on comparison operators.

thanks

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