docs:programming:php:php_notes

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docs:programming:php:php_notes [2007/01/23 22:45] – (old revision restored) 127.0.0.1docs:programming:php:php_notes [2008/08/03 00:25] (current) – external edit 127.0.0.1
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 </code> </code>
  
 +
 +
 +===== $PHP_SELF =====
 +$PHP_SELF is a variable which represents the currently executing script (the name of the file you are viewing/running).
  
 ===== Dynamic Variables ===== ===== Dynamic Variables =====
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  echo ${$var[1]};  // array example  echo ${$var[1]};  // array example
 </code> </code>
 +
  
 ===== Objects ===== ===== Objects =====
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 } }
 </code> </code>
-More information is available at http://www.php.net/oop+More information is available at: 
 +  * (PHP4) http://us3.php.net/manual/en/language.oop.php 
 +  * (PHP5) http://us3.php.net/manual/en/language.oop5.php 
 + 
 + 
 + 
 +===== list() ===== 
 +list — Assign variables as if they were an array: 
 +==== Example 298 ==== 
 +<code php> 
 +<?php 
 + 
 +$info = array('coffee', 'brown', 'caffeine'); 
 + 
 +// Listing all the variables 
 +list($drink, $color, $power) = $info; 
 +echo "$drink is $color and $power makes it special.\n"; 
 + 
 +// Listing some of them 
 +list($drink, , $power) = $info; 
 +echo "$drink has $power.\n"; 
 + 
 +// Or let's skip to only the third one 
 +list( , , $power) = $info; 
 +echo "I need $power!\n"; 
 + 
 +?>  
 +</code> 
 + 
 +==== Example 299 ==== 
 +<code php> 
 +<table> 
 + <tr> 
 +  <th>Employee name</th> 
 +  <th>Salary</th> 
 + </tr> 
 + 
 +<?php 
 + 
 +$result = mysql_query("SELECT id, name, salary FROM employees", $conn); 
 +while (list($id, $name, $salary) = mysql_fetch_row($result)) { 
 +   echo " <tr>\n" . 
 +         "  <td><a href=\"info.php?id=$id\">$name</a></td>\n" . 
 +         "  <td>$salary</td>\n" . 
 +         " </tr>\n"; 
 +} 
 + 
 +?> 
 + 
 +</table> 
 +</code>
  
 ===== break n ===== ===== break n =====
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 It may be easier to write them using the second method if you have intermixed code and HTML. It may be easier to write them using the second method if you have intermixed code and HTML.
 </code> </code>
 +
  
 ===== => and -> symbols ===== ===== => and -> symbols =====
   * use <html>&#061;&gt;</html> with the foreach command on associative arrays   * use <html>&#061;&gt;</html> with the foreach command on associative arrays
     * foreach($array as $key<html>&#061;&gt;</html>$value)...     * foreach($array as $key<html>&#061;&gt;</html>$value)...
-    * to assign values to associative arrays, use the = sign+    * to assign values to associative arrays (inside the array function), use <html>&#061;&gt;</html>:<code php> 
 +$foo = array( 
 + "fname" => "John", 
 + "lname" => "Doe", 
 + "planet" => "Earth" 
 +); 
 +</code> 
 +    * to assign values to associative arrays (line by line), use the = sign
       * $array[item1] = "orange"       * $array[item1] = "orange"
       * $array[item2] = "banana"       * $array[item2] = "banana"
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     * $this<html>&#045;&gt;</html>functionName()     * $this<html>&#045;&gt;</html>functionName()
     * $this<html>&#045;&gt;</html>variableName     * $this<html>&#045;&gt;</html>variableName
 +
 +
 +
 +===== testing for variable existence =====
 +<code php>
 +// note - a variable could be set, but set with no value
 +if(isset($var))
 +  // do something
 +
 +// is the variable set and not empty
 +if(!empty($var))
 +  // do something
 +
 +// using the variable name as a test is the same as !empty
 +if($var)
 +  // do something
 +</code>
 +
  
 ===== testing for string equality ===== ===== testing for string equality =====
 <code> <code>
 +// use this when testing for simple string equality
 +if($var == "match string")
 +  // do something
 +
 +// three equals (===) check for equality of value and type
 +// i.e. 0.0 == 0 (true)
 +// i.e. 0.0 === 0 (false)
 +if($var === "match string")
 +  // do something
 +
 +// strcasecmp and strcmp will return higher, lower or zero depending
 +// if the match string is considered higher, lower or equal
 if(strcasecmp($var, "match string")==0) if(strcasecmp($var, "match string")==0)
   // do something   // do something
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 ===== accessing class members from another function ===== ===== accessing class members from another function =====
   * if you add a normal function in a file after a class has been defined, and you want to access the members of the class within the normal function, you need to declare the class as "global" first   * if you add a normal function in a file after a class has been defined, and you want to access the members of the class within the normal function, you need to declare the class as "global" first
 +
 +===== require/include =====
 +  * if you use require or include, make sure to use a relative or full path to avoid duplicating a filename already in the php include path (such as DB.php)
 +
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  • Last modified: 2008/08/03 00:25
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