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TUTORIAL - Arrays and PHP example with checkbox

Posted by admin On April - 30-2009

An array in PHP is actually an ordered map. A map is a type that maps values to keys. This type is optimized in several ways, so you can use it as an array, or a list (vector), hashtable (which is an implementation of a map), dictionary, collection, stack, queue and probably more. As you may have another PHP array as a value, you can also quite easily simulate trees.

PHP Array Syntax: Create an Array

language-construct array () is used to create an array in PHP. See an example

array ([key =>] value
...
)
key: key can be an integer or string
value: A value can be any PHP type

Examples
$ Arr = array ("foo" => "bar", 12 => true);
echo $ arr ["foo"]; this will print bar
echo $ arr [12], this will print a

If you provide the brackets with no key specified, then the maximum value of existing indexes is taken as a whole key. see below

$ Arr = array (5 => 1, 12 => 2); This will create an array with 2 elements
$ Arr [] = 56; new key will be maximum ie a key + $ arr [13] = 56
$ Arr ["x"] = 42;

This adds a new element into the array with the key "x"

array (5 => 43, 32, 56, "b" => 12); The Same This array is the following.
array (5 => 43, 6 => 32, 7 => 56, "b" => 12);

Following example will show that we can use an array of HTML form input.

Handling HTML form input arrays to PHP scripts

HTML form with array

<input type="checkbox" name="selected_ids[]" value="1">
<input type="checkbox" name="selected_ids[]" value="2">
<input type="checkbox" name="selected_ids[]" value="3">
<input type="checkbox" name="selected_ids[]" value="11">
<input type="checkbox" name="selected_ids[]" value="12">
<input type="checkbox" name="selected_ids[]" value="13">

When you submit the form above, will generate $ _POST ['selected_ids'] [] array to the form handling php script. This array holds all selected checkbox values above HTML form. foreach () construct can be used to extract values of the matrix. Following sample code will show how we can extract these values from the return array.

foreach ($ _POST ['selected_ids'] as $ key => $ value) {
echo "Key: $ key, Value: $ value <br>";
}

for example, 1.2 and 12 are selected from the HTML form above then above code will print

Key: 0 Value: 1
Key: 1 Value: 2
Key: 2 Value: 12