PHP using foreach to iterate over arrays more efficient _php tutorials

There are two ways to use foreach ():

foreach (Array_Name as $value)    {       statement;    }

The array_name here is the name of the array you want to traverse, each time the value of the current element of the Array_Name array is assigned to $value, and the subscript inside the array moves down one step, that is, the next loop returns to the next element.

foreach (array_name as $key = = $value)    {        statement;      

The difference between this and the first method is that there is a $key, that is, in addition to assigning the value of the current element to $value, the key value of the current element is assigned to the variable $key in each loop. The key value can be a subscript value or a string. For example, "0" in Book[0]=1, book[id]= "id" in "001".

Program Examples:

1

 
  '; $a = array (1, 2, 3,); foreach ($a as $v) {   echo "current value of". $a. ":". $v. "
";}? >//Run result foreach example 1:value only current value of $a: 1Current value of $a: 2Current value of $a: 3Current value O F $a: 17

2

/*-------------------------------------------------------------------------*//* foreach example 2:value (with key Printed for illustration) */echo '
'.'
'." foreach example 2:value (with key printed for illustration) "."
'; $a = array (1, 2, 3,); $i = 0; /* For illustrative purposes only */foreach ($a as $v) {    echo "" $a [$i] + $v "."
';    $i + +;} Program Run result foreach example 2:value (with key printed for illustration) $a [0] = = 1$a[1] = 2$a[2] + 3$a[3] + 1 7

3

/*-------------------------------------------------------------------------*//* foreach example 3:key and value */ Echo '
'.'
'." foreach Example 3:key and value "."
'; $a = array (    "one" = 1, "one" + =    2,    "three" = 3,    "Seventeen"); foreach ($a as $k = = $v) {    echo "" $a [$k] = $v "."
';} Program Run result foreach example 3:key and value $a [one] = 1$a[two] = 2$a[three] + 3$a[seventeen] + 17

4

/*-------------------------------------------------------------------------*//* foreach Example 4: Multi-dimensional Arrays */echo '
'.'
'." foreach Example 4:multi-dimensional arrays ". '
'; $a = array (); $a [0][0] = "a"; $a [0][1] = "B"; $a [1][0] = "Y"; $a [1][1] = "Z"; foreach ($a as $v 1) {    foreach ($v 1 as $v 2) {        echo "$v 2" n ";    }} Program Run result foreach example 4:multi-dimensional arrays a b y Z

5

/*-------------------------------------------------------------------------*//* foreach Example 5:dynamic arrays */ Echo '
'.'
'." foreach Example 5:dynamic arrays ". '
'; foreach (Array (1, 2, 3, 4, 5) as $v) {    echo "$v" n ";} Program Run result foreach example 5:dynamic arrays 1 2 3 4 5

You can also use this:

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   $value):?>
 
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   class= "Onlink" >
 
  
 
  
 
  

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