Difference between revisions of "PHP 2"

From Ilianko
Line 6: Line 6:
 
  $myString = 'ilian';
 
  $myString = 'ilian';
 
  $myZeroString = '';
 
  $myZeroString = '';
 +
 +
 +
=== type casting ===
 +
 +
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 26: Line 40:
 
  //var_dump(  $myZeroString === $myZero );
 
  //var_dump(  $myZeroString === $myZero );
 
  //var_dump(  $myString === $myZero );
 
  //var_dump(  $myString === $myZero );
 +
 +
 +
<table class="doctable table">
 +
  <caption><strong>Comparisons of <var class="varname"><var class="varname">$x</var></var> with PHP functions</strong></caption>
 +
 
 +
    <thead>
 +
    <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>
 +
  
 
== if ==
 
== if ==

Revision as of 10:14, 20 October 2013

Условни оператори 

$myVar = 1;
$myZero = 0;
$myString = 'ilian';
$myZeroString = ;


type casting

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(  $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 );


<thead> </thead> <tbody class="tbody"> </tbody>
Comparisons of $x with PHP functions
Expression <a href="function.gettype.php" class="function">gettype()</a> <a href="function.empty.php" class="function">empty()</a> <a href="function.is-null.php" class="function">is_null()</a> <a href="function.isset.php" class="function">isset()</a> <a href="language.types.boolean.php" class="type boolean">boolean</a> : if($x)
$x = ""; <a href="language.types.string.php" class="type string">string</a> TRUE FALSE TRUE FALSE
$x = null; <a href="language.types.null.php" class="type NULL">NULL</a> TRUE TRUE FALSE FALSE
var $x; <a href="language.types.null.php" class="type NULL">NULL</a> TRUE TRUE FALSE FALSE
$x is undefined <a href="language.types.null.php" class="type NULL">NULL</a> TRUE TRUE FALSE FALSE
$x = array(); <a href="language.types.array.php" class="type array">array</a> TRUE FALSE TRUE FALSE
$x = false; <a href="language.types.boolean.php" class="type boolean">boolean</a> TRUE FALSE TRUE FALSE
$x = true; <a href="language.types.boolean.php" class="type boolean">boolean</a> FALSE FALSE TRUE TRUE
$x = 1; <a href="language.types.integer.php" class="type integer">integer</a> FALSE FALSE TRUE TRUE
$x = 42; <a href="language.types.integer.php" class="type integer">integer</a> FALSE FALSE TRUE TRUE
$x = 0; <a href="language.types.integer.php" class="type integer">integer</a> TRUE FALSE TRUE FALSE
$x = -1; <a href="language.types.integer.php" class="type integer">integer</a> FALSE FALSE TRUE TRUE
$x = "1"; <a href="language.types.string.php" class="type string">string</a> FALSE FALSE TRUE TRUE
$x = "0"; <a href="language.types.string.php" class="type string">string</a> TRUE FALSE TRUE FALSE
$x = "-1"; <a href="language.types.string.php" class="type string">string</a> FALSE FALSE TRUE TRUE
$x = "php"; <a href="language.types.string.php" class="type string">string</a> FALSE FALSE TRUE TRUE
$x = "true"; <a href="language.types.string.php" class="type string">string</a> FALSE FALSE TRUE TRUE
$x = "false"; <a href="language.types.string.php" class="type string">string</a> FALSE FALSE TRUE TRUE


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

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