PHP FOR STATEMENT

FOR


The for function is the more complex sibling of the while function and provides a more streamline and complex looping mechanism.  The for function takes three expressions; the first expression is evaluated by default at the first iteration of the loop, the second expression is evaluated at the beginning of each iteration (and determines if the loop will continue) and the third expression is evaluated at the conclusion of each loop.  Any of the expressions can be empty and the logic that would take place in the expression can be substituted in the body of the function itself.  The statement list within the for code body can consist of one or more statements. 


for (expression1; expression2; expression3) 
{ 
    -- statements that execute while the expressions evaluates false 
} 




The following examples demonstrate how the for iterative control statement can work: 




<?php 
    for ($ctemp = 0; $ctemp <= 20; $ctemp = $ctemp + 1) { 
        $ftemp = 32 + $ctemp / 5 * 9; 
        echo "$ctemp -> $ftemp<br>"; 
    } 
?> 
<?php 
    for ($ctemp = 0; ; $ctemp = $ctemp + 1) { 
        $ftemp = 32 + $ctemp / 5 * 9; 
        echo "$ctemp -> $ftemp<br>"; 
        if ($ctemp >= 20) break; 
    } 
?> 
<?php 
    $ctemp = 0; 
    for (;;) { 
        $ftemp = 32 + $ctemp / 5 * 9; 
        echo "$ctemp -> $ftemp<br>"; 
        if ($ctemp >= 20) break; 
        $ctemp = $ctemp + 1; 
    } 
?> 


FOREACH


       The foreach function is the iterative control statement that is designed specifically for handling arrays (and objects as of PHP 5). There are two ways of using the foreach iterative control statement.  The first ways is by looping over the array given by the array_expression and assigning the current array element to the $value variable.   




foreach (array_expression as $value) { 
    -- statements that execute until the array reaches the end or a   
       manual break is inserted 
} 


The second way of using the foreach function is similar to the first, except the element value is assigned to a $key variable. 




foreach (array_expression as $key => $value) { 
    -- statements that execute until the array reaches the end or a   
       manual break is inserted 
} 


Each time the foreach command is initiated, the internal pointer to the array is reset and each iteration advances the pointer one element.  The following examples demonstrate how the  foreach iterative control statement can work: 






<?php 
    $last_name = array("Smith", "Jones", "Sanchez", "Green"); 
    foreach ($last_name as $individual) { 
        print "Last Name = $individual<br>"; 
    } 
?> 



<?php 
    $wk_temp = array( 
                'Sunday' => 13, 
                'Monday' => 12, 
                'Tuesday' => 11, 
                'Wednesday' => 13, 
                'Thursday' => 15, 
                'Friday' => 17, 
                'Saturday' => 9); 
    $wk_avg = 0; 
    foreach($wk_temp as $day => $temp) { 
        echo "$day = $temp<br>"; 
        $wk_avg = $wk_avg + $temp; 
    } 
    $wk_avg = $wk_avg / 7; 
    echo "The average temperature for the week was $wk_avg"; 
?>