<?php

// 乍看起来下面的输出是 'true'

echo (true?'true':false?'t':'f');

// 然而，上面语句的实际输出是't'，因为三元运算符是从左往右计算的

// 下面是与上面等价的语句，但更清晰

echo ((true ? 'true' : 'false') ? 't' : 'f');

// here, you can see that the first expression is evaluated to 'true', which

// in turn evaluates to (bool)true, thus returning the true branch of the

// second ternary expression.

?> 

<?php

$output = `ls -al`;

echo "<pre>$output</pre>";

?> 

<?php

$a = "Hello ";

$b = $a . "World!"; // now $b contains "Hello World!"

$a = "Hello ";

$a .= "World!";     // now $a contains "Hello World!"

?> 

<?php

$a = array("apple", "banana");

$b = array(1 => "banana", "0" => "apple");

var_dump($a == $b); // bool(true)

var_dump($a === $b); // bool(false)

?> 

<?php

/* 不正确的使用方法： */

if($a > $b):

    echo $a." is greater than ".$b;

else if($a == $b): // 将无法编译

    echo "The above line causes a parse error.";

endif;

/* 正确的使用方法： */

if($a > $b):

    echo $a." is greater than ".$b;

elseif($a == $b): // 注意使用了一个单词的 elseif

    echo $a." equals ".$b;

else:

    echo $a." is neither greater than or equal to ".$b;

endif;

?> 

<?php if ($a == 5): ?>

A is equal to 5  //HTML 内容"A is equal to 5"用替代语法嵌套在 if 语句中。该 HTML 的内容仅在 $a 等于 5 时显示。

<?php endif; ?> 

<?php

if ($a == 5):

    echo "a equals 5";

    echo "...";

elseif ($a == 6):

    echo "a equals 6";

    echo "!!!";

else:

    echo "a is neither 5 nor 6";

endif;

?> 

<?php

/* example 1 */

$i = 1;

while ($i <= 10) {

    echo $i++;  /* the printed value would be

                    $i before the increment

                    (post-increment) */

}

/* example 2 */

$i = 1;

while ($i <= 10):

    print $i;

    $i++;

endwhile;

?> 

<?php

$arr = array("one", "two", "three");

reset($arr);

while (list(, $value) = each($arr)) {

    echo "Value: $value<br>\n";

}

foreach ($arr as $value) {

    echo "Value: $value<br />\n";

}

?> 

<?php

$arr = array("one", "two", "three");

reset($arr);

while (list($key, $value) = each($arr)) {

    echo "Key: $key; Value: $value<br />\n";

}

foreach ($arr as $key => $value) {

    echo "Key: $key; Value: $value<br />\n";

}

?> 

<?php

$array = [

    [1, 2],

    [3, 4],

];

foreach ($array as list($a)) {

    // Note that there is no $b here.

    echo "$a\n";

}

?> 

1

3

<?php

$arr = array('one', 'two', 'three', 'four', 'stop', 'five');

while (list (, $val) = each($arr)) {

    if ($val == 'stop') {

        break;    /* You could also write 'break 1;' here. */

    }

    echo "$val<br />\n";

}

/* 使用可选参数 */

$i = 0;

while (++$i) {

    switch ($i) {

    case 5:

        echo "At 5<br />\n";

        break 1;  /* 只退出 switch. */

    case 10:

        echo "At 10; quitting<br />\n";

        break 2;  /* 退出 switch 和 while 循环 */

    default:

        break;

    }

}

?> 

<?php

  for ($i = 0; $i < 5; ++$i) {

      if ($i == 2)

          continue

      print "$i\n";

  }

?> 

<?php

goto loop;

for($i=0,$j=50; $i<100; $i++) {

  while($j--) {

    loop:

  }

}

echo "$i = $i";

?> 

以上例程会输出：