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• **unknown user**
  
  

  • Rank: Helper
  • Registered: Mar 16, 2002
  • Last visit: Oct 21, 2009
  • Posts: 842

  Posted: Dec 03, 2004 - 06:41 AM

  I'm wondering if there is a way to check and see if a variable is declared or not, and if not, to set it.
  
  

  Code

  if (!defined($country)) {
  $country="0";
  }

  
  
  Probably the above won't work, though I have yet to actually test it. Does anyone have any tips for me as to what I can try?
  
  Thanks in advance for any assistance.

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• **unknown user**
  
  

  • Rank: Senior
  • Registered: Mar 16, 2002
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  • Posts: 2330

  Posted: Dec 03, 2004 - 10:09 AM

  Code

  if (!isset($Var)) {
  $Var = 'SomeValue';
  }

  
  ...Or, you could also do:
  
  

  Code

  if ($Var == '') {
  $Var = 'SomeValue';
  }

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• Lobos
  
  

  • Rank: Expert
  • Registered: Dec 02, 2002
  • Last visit: Apr 30, 2010
  • Posts: 1474

  Posted: Dec 03, 2004 - 03:23 PM

  LOL I like the second one:
  
  if ($Var == "") {
  $Var = 'SomeValue';
  }
  
  it is so... logical LOL
  
  Now I wonder, what if you actually wanted to set a var as "" - ie nothing - would isset return false here ?
  
  eg
  
  $var=""; // I have "set" this var as "" so I have actually set the var !
  
  if isset returns false here I think it is illogical and isset should be changed to isvar, ie is there a var?
  
  --
  -Lobos
  Professional PHP Framework Services: Concept, Development and Deployment

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• **unknown user**
  
  

  • Rank: Senior
  • Registered: Mar 16, 2002
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  • Posts: 2204

  Posted: Dec 03, 2004 - 03:32 PM

  isset will return true even if empty.. empty() is the equivilent of $var == ''
  
  $var = '';
  
  if(empty($var)){
  // var is empty
  }
  
  if(isset($var)){
  // true, $var exists
  }
  
  isset I think was intended to be based on parameters index.php?module=this .. "module" being the parameter, "this" being the variable or value ..even without "this" the parameter module 'is set' ..
  
  -IR

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• **unknown user**
  
  

  • Rank: Senior
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  • Posts: 2330

  Posted: Dec 03, 2004 - 04:08 PM

  Interestingly, it will return TRUE. Try it out:
  

  Code

  <?php
  
      $Var = '';
     
      if (!isset($Var))
      {
          echo '$Var not set';
      }
      else
      {
          echo '$Var is set';
      }
  ?>

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• **unknown user**
  
  

  • Rank: Senior
  • Registered: Mar 16, 2002
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  • Posts: 2204

  Posted: Dec 03, 2004 - 04:50 PM

  ..they're often used in conjunction:
  
  $var = '';
  
  if(isset($var) AND !empty($var)){ // parameter is set, but has a null/0 value, so kill it
  echo 'all is well';
  } else {
  die 'no value..kill it.';
  }
  
  ps: typically defined() is used for constants.. as we do with languages and settings in the API

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• **unknown user**
  
  

  • Rank: Helper
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  Posted: Dec 06, 2004 - 12:42 AM

  Thanks guys. Got it working, but was away for the weekend so couldn't respond.

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• **unknown user**
  
  

  • Rank: Senior
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  • Posts: 2330

  Posted: Dec 06, 2004 - 05:21 AM

  No prob....thanks for getting back.

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• **unknown user**
  
  

  • Rank: Senior
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  • Posts: 2243

  Posted: Dec 06, 2004 - 06:15 AM

  alarconcepts

  
  Interestingly, it will return TRUE. Try it out:
  

  
  
  The reason a variable set to '' is considered set is probably because it is not NULL. Empty and NULL are not the same thing. I guess the real test is whether the variable exists, not so much if the variable has a value.
  
  Frank

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• **unknown user**
  
  

  • Rank: Senior
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  Posted: Dec 06, 2004 - 06:42 AM

  php.net

  
  empty() returns FALSE if var has a non-empty and non-zero value. In otherwords, "", 0, "0", NULL, FALSE, array(), and var $var; are all considered empty.
  

  
  http://us2.php.net/empty
  
  

  php.net

  isset -- Determine whether a variable is set

  
  (..regardless of value.)
  http://us2.php.net/isset

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• Slugger
  
  

  • Rank: Expert
  • Registered: Mar 11, 2003
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  • Posts: 1104

  Posted: Dec 08, 2004 - 06:02 PM

  In my oppinion, this is so much ado about nothing.
  
  I'm sorry I couldn't resist.
  
  Slugger

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• HalbrookTech
  
  

  • Rank: Developer
  • Registered: Dec 31, 1969
  • Last visit: Jun 01, 2010
  • Posts: 6859

  Posted: Dec 08, 2004 - 06:15 PM

  alarconcepts

  Interestingly, it will return TRUE.

  
  
  As well it should, if you want to know if it's been defined as anything, then use isset, if you want to know if it's set to a certian value, use the other method.
  
  --
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