Difference between revisions of "PHP 2"

From Ilianko
Line 7: Line 7:
 
  $myZeroString = '';
 
  $myZeroString = '';
  
 +
var_dump($myVar);
  
=== type casting ===
+
  http://php.net/manual/en/types.comparisons.php
 
 
Да се внимава със загубата на информация
 
   
 
 
 
 
$myVar = 1.1;
 
$myVar = (int) $myVar;
 
$myVar = (string) $myVar;
 
$myVar = (bool) $myVar;
 
 
 
var_dump($myVar);
 
  
 
  //var_dump(  $myZero = $myVar );
 
  //var_dump(  $myZero = $myVar );
Line 41: Line 31:
 
  //var_dump(  $myString === $myZero );
 
  //var_dump(  $myString === $myZero );
  
 +
Да се внимава със загубата на информация
  
<table class="doctable table">
+
$myVar = 1.1;
  <caption><strong>Comparisons of <var class="varname"><var class="varname">$x</var></var> with PHP functions</strong></caption>
+
$myVar = (int) $myVar;
 
+
$myVar = (string) $myVar;
    <thead>
+
$myVar = (bool) $myVar;
    <tr>
 
      <th>Expression</th>
 
      <th> <span class="function"><a href="function.gettype.php" class="function">gettype()</a></span></th>
 
      <th> <span class="function"><a href="function.empty.php" class="function">empty()</a></span></th>
 
      <th> <span class="function"><a href="function.is-null.php" class="function">is_null()</a></span></th>
 
      <th> <span class="function"><a href="function.isset.php" class="function">isset()</a></span></th>
 
      <th><span class="type"><a href="language.types.boolean.php" class="type boolean">boolean</a></span> : <em>if($x)</em></th>
 
    </tr>
 
 
 
    </thead>
 
 
 
    <tbody class="tbody">
 
    <tr>
 
      <td><em>$x = &quot;&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = null;</em></td>
 
      <td><span class="type"><a href="language.types.null.php" class="type NULL">NULL</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>var $x;</em></td>
 
      <td><span class="type"><a href="language.types.null.php" class="type NULL">NULL</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><var class="varname"><var class="varname">$x</var></var> is undefined</td>
 
      <td><span class="type"><a href="language.types.null.php" class="type NULL">NULL</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = array();</em></td>
 
      <td><span class="type"><a href="language.types.array.php" class="type array">array</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = false;</em></td>
 
      <td><span class="type"><a href="language.types.boolean.php" class="type boolean">boolean</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = true;</em></td>
 
      <td><span class="type"><a href="language.types.boolean.php" class="type boolean">boolean</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = 1;</em></td>
 
      <td><span class="type"><a href="language.types.integer.php" class="type integer">integer</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = 42;</em></td>
 
      <td><span class="type"><a href="language.types.integer.php" class="type integer">integer</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = 0;</em></td>
 
      <td><span class="type"><a href="language.types.integer.php" class="type integer">integer</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = -1;</em></td>
 
      <td><span class="type"><a href="language.types.integer.php" class="type integer">integer</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = &quot;1&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = &quot;0&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
    </tr>
 
 
 
    <tr>
 
      <td><em>$x = &quot;-1&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
  
    <tr>
 
      <td><em>$x = &quot;php&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
  
    <tr>
 
      <td><em>$x = &quot;true&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
  
    <tr>
 
      <td><em>$x = &quot;false&quot;;</em></td>
 
      <td><span class="type"><a href="language.types.string.php" class="type string">string</a></span></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>FALSE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
      <td><strong><code>TRUE</code></strong></td>
 
    </tr>
 
  
    </tbody>
 
 
 
  </table>
 
  
  

Revision as of 10:17, 20 October 2013

Условни оператори

$myVar = 1;
$myZero = 0;
$myString = 'ilian';
$myZeroString = ;
var_dump($myVar);
http://php.net/manual/en/types.comparisons.php
//var_dump(  $myZero = $myVar );
//var_dump(  $myVar = $myZero );
//var_dump(  $myZero = $myString );

//var_dump(  $myZero == $myVar );
//var_dump(  $myZero == $myString ); 
//var_dump(  $my == $myZeroString ); 

//var_dump(  $myVar === $myString ); 
//var_dump(  $myVar === $myZeroString ); 
//var_dump(  $myVar == $myString );
//var_dump(  $myZeroString == $myVar );
//var_dump(  $myZeroString == $myZero );
//var_dump(  $myZeroString == $myString );

//var_dump(  $myZeroString === $myString );
//var_dump(  $myZeroString === $myVar );
//var_dump(  $myZeroString === $myZero );
//var_dump(  $myString === $myZero );

Да се внимава със загубата на информация

$myVar = 1.1;
$myVar = (int) $myVar;
$myVar = (string) $myVar;
$myVar = (bool) $myVar;




if

if

$myVar = 'Ivan';

if($myVar == 'logged'){
  echo 'You are logged';
}
echo 'Click Next';

if else

$myVar = 'Ivan';
if($myVar == 'logged'){
  echo 'You are logged';
}
else {
  echo 'Please login';
}
echo 'Click Next';

if elseif else

if($myVar == 'logged'){
  $text = 'You are logged';
}
elseif($myVar == 'guest') {
  $text = 'Please choose name';
}
else
  $text = 'Please register
echo $text.' Click Next';

() ? :

$text = ($myVar == 'logged') ? 'You are logged' : 'Please login';
echo $text.' Click Next';


for

for

foreach

while

switch