PHP: range - Manual

Description

array range ( number low, number high [, number step] )

range() returns an array of elements from low to high, inclusive. If low > high, the sequence will be from high to low.

New parameter: The optional step parameter was added in 5.0.0.

If a step value is given, it will be used as the increment between elements in the sequence. step should be given as a positive number. If not specified, step will default to 1.

Example 1. range() examples

<?php // array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) foreach (range(0, 12) as $number) { echo $number; } // The step parameter was introduced in 5.0.0 // array(0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100) foreach (range(0, 100, 10) as $number) { echo $number; } // Use of character sequences introduced in 4.1.0 // array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i'); foreach (range('a', 'i') as $letter) { echo $letter; } // array('c', 'b', 'a'); foreach (range('c', 'a') as $letter) { echo $letter; } ?>

Note: Prior to PHP 4.1.0, range() only generated incrementing integer arrays. Support for character sequences and decrementing arrays was added in 4.1.0. Character sequence values are limited to a length of one. If a length greater than one is entered, only the first character is used.

Caution

In PHP versions 4.1.0 through 4.3.2, range() sees numeric strings as strings and not integers. Instead, they will be used for character sequences. For example, "4242" is treated as "4".

See also shuffle(), array_fill(), and foreach.

User Contributed Notes
range

derek at php dot net
08-May-2005 08:13


This should emulate range() a little better.


<?php


function range_wroar($low, $high, $step = 1) {


    $arr = array();


    $step = (abs($step)>0)?abs($step):1;


    $sign = ($low<=$high)?1:-1;


    if(is_numeric($low) && is_numeric($high)) {


        //numeric sequence


        for ($i = (float)$low; $i*$sign <= $high*$sign; $i += $step*$sign)


            $arr[] = $i;


    }    else    {


        //character sequence


        if (is_numeric($low)) 


            return $this->range($low, 0, $step);


        if (is_numeric($high))


            return $this->range(0, $high, $step);


        $low = ord($low);


        $high = ord($high);


        for ($i = $low; $i*$sign <= $high*$sign; $i += $step*$sign) {


                


            $arr[] = chr($i);


        }


    }


    return $arr;


}


?>

j dot gizmo at aon dot at
23-Sep-2004 06:23


i figured i'd add some more functionality to the myRange() functions below.

now you can, besides giving a $step parameter,

1. count backwards

2. count with letters

3. give whatever parameter you want, there's nothing (i know of) that will cause an endless loop (try a negative $step for the previous function....)



<?php

function myRange($num1, $num2, $step=1)

{

    if (is_numeric($num1) && is_numeric($num2))

    {

        //we have a numeric range

        $step = ( abs($step)>0 ? abs($step) : 1 ); //make $step positive

        $dir = ($num1<=$num2 ? 1 : -1); //get the direction

        for($i = (float)$num1; $i*$dir <= $num2*$dir; $i += $step*$dir)

        {

            $temp[] = $i;

        }

    }

    else

    {

        //we have a character range

        $num1=ord((string)$num1); //convert to ascii value

        $num2=ord((string)$num2);

        $step = ( abs($step)>0 ? abs($step) : 1 ); //make $step positive

        $dir = ($num1<=$num2 ? 1 : -1); //get direction

        for($i = $num1; $i*$dir <= $num2*$dir; $i += $step*$dir)

        {

            $temp[] = chr($i);

        }

    }

    return $temp;

}



print_r(myRange( 1, 3, 0.5 )); //you can use fractional steps

print_r(myRange( "a", "k", 3 )); //or count letters

print_r(myRange( "5", "9" )); //numbers are detected even if hidden in strtings

print_r(myRange( "!", "%", 1/pi() )); //or mess around with senseless parameters



?>

donwilson at gmail dot com
31-Aug-2004 11:38


To speed your MyRange() function, I have created a much nicer function with less code to sift through to include the step parameter.



<?php    

    // range() limitation for PHP <5.0.0

    function myRange($num1, $num2, $step=1)

    {

        for($i = $num1; $i <= $num2; $i += $step)

        {

            $temp[] = $i;

        }

        

        return $temp;

    }

?>



For whatever reason my comment was deleted..?

Forrester at tfcustomized dot com
17-May-2004 09:57


Since users of < PHP 5.0.0 don't have the option of the step parameter, I've created a little function to account for it:



@USAGE: (int low, int high [, int step])



function myRange($low,$high,$step=1)

{

$ranArray = range($low,$high);

$step--;

$keys = count($ranArray);

    for($i=0;$i<$keys;$i++)

    {

    $retArray[] = $ranArray[$i];

    $i = $i + $step;

    }

return $retArray;

}



// Example usage:

print_r(myRange(1,11,2));

// Returns the array:

// [0] => 1 

// [1] => 3 

// [2] => 5 

// [3] => 7 

// [4] => 9 

// [5] => 11

auscoff at no-spam dot yahoo dot com
06-Mar-2002 07:40


If you set number range via variables (eg., range($from, $to)) make sure 

you've set type of the variables to integer or your code won't work with version 4.1.0 and above.



$from = 0;

$to = 7;



foreach( range((int) $from, (int) $to) as $number ) {

    print "$number\n";

}