php and variable variables with array

Question

Trying to end up with 7 arrays ($mon, $tue, $wed, $thu, $fri, $sat, $sun) that contain a value of either 0 or 1 for each hour of the day given initial array $hours. $hours is just a posted array that contains user selected hours for each day of the week.

I believe the problem is my use of variable variables ($$day) as my weekday arrays all return null ($mon, $tue, $wed, $thu, $fri, $sat, $sun). Any assistance would be appreciated.

$hours =

Array
(
    [mon] => Array
        (
            [0] => 12pm
            [1] => 1pm
            [2] => 2pm
            [3] => 3pm
            [4] => 4pm
            [5] => 5pm
            [6] => 6pm
            [7] => 7pm
        )

    [tue] => Array
        (
            [0] => 12am
            [1] => 1am
            [2] => 2am
            [3] => 3am
            [4] => 4am
            [5] => 5am
            [6] => 6am
            [7] => 7am
            [8] => 8am
            [9] => 9am
            [10] => 10am
            [11] => 11am
            [12] => 12pm
            [13] => 1pm
            [14] => 2pm
            [15] => 3pm
            [16] => 4pm
            [17] => 5pm
            [18] => 6pm
            [19] => 7pm
            [20] => 8pm
            [21] => 10pm
            [22] => 11pm
        )

    [sun] => Array
        (
            [0] => 12am
        )

)

the code :

//create an array of weekdays
$weekdays = array('mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun');

foreach($weekdays as $day)
{

    //set hours for each day using variable variables $$day = mon, tue, wed, etc
    if($hours[$day])
    {
        $$day['12a'] = in_array("12am", $hours[$day]) == 1 ? 1 : 0;
        $$day['1a'] = in_array("1am", $hours[$day]) == 1 ? 1 : 0;
        $$day['2a'] = in_array("2am", $hours[$day]) == 1 ? 1 : 0;
        $$day['3a'] = in_array("3am", $hours[$day]) == 1 ? 1 : 0;
        $$day['4a'] = in_array("4am", $hours[$day]) == 1 ? 1 : 0;
        $$day['5a'] = in_array("5am", $hours[$day]) == 1 ? 1 : 0;
        $$day['6a'] = in_array("6am", $hours[$day]) == 1 ? 1 : 0;
        $$day['7a'] = in_array("7am", $hours[$day]) == 1 ? 1 : 0;
        $$day['8a'] = in_array("8am", $hours[$day]) == 1 ? 1 : 0;
        $$day['9a'] = in_array("9am", $hours[$day]) == 1 ? 1 : 0;
        $$day['10a'] = in_array("10am", $hours[$day]) == 1 ? 1 : 0;
        $$day['11a'] = in_array("11am", $hours[$day]) == 1 ? 1 : 0;
        $$day['12p'] = in_array("12pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['1p'] = in_array("1pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['2p'] = in_array("2pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['3p'] = in_array("3pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['4p'] = in_array("4pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['5p'] = in_array("5pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['6p'] = in_array("6pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['7p'] = in_array("7pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['8p'] = in_array("8pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['9p'] = in_array("9pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['10p'] = in_array("10pm", $hours[$day]) == 1 ? 1 : 0;
        $$day['11p'] = in_array("11pm", $hours[$day]) == 1 ? 1 : 0;
    }

}

//debugging only to see variable values
file_put_contents('/home/test/public_html/file.txt', print_r($hours, true));
file_put_contents('/home/test/public_html/file-mon.txt', print_r($mon, true));
file_put_contents('/home/test/public_html/file-tue.txt', print_r($tue, true));
file_put_contents('/home/test/public_html/file-wed.txt', print_r($wed, true));
file_put_contents('/home/test/public_html/file-thu.txt', print_r($thu, true));
file_put_contents('/home/test/public_html/file-fri.txt', print_r($fri, true));
file_put_contents('/home/test/public_html/file-sat.txt', print_r($sat, true));
file_put_contents('/home/test/public_html/file-sun.txt', print_r($sun, true));

EDIT - ending solution used :

With a few changes as necessary for other aspects of my script.

//decode the json array posted
$hours = json_decode($_POST['hours'], true);

//set array of weekdays
$weekdays = array(1 => 'mon', 2 => 'tue', 3 => 'wed', 4 => 'thu', 5 => 'fri', 6 => 'sat', 7 => 'sun');

//set array of hour values
$hourDefs = array('12am', '1am', '2am', '3am', '4am', '5am', '6am', '7am', '8am', '9am', '10am', '11am', '12pm', '1pm', '2pm', '3pm', '4pm', '5pm', '6pm', '7pm', '8pm', '9pm', '10pm', '11pm');

//set result output array
$output = array();

foreach($weekdays as $day=>$day_value)
{   
    //set hours for each day using variable variables ${$day} = mon, tue, wed, etc
    if(isset($hours[$day_value]))
    {
        foreach($hourDefs as $def)
        {
            $output[$day_value][$def] = in_array($def, $hours[$day_value]) == 1 ? 1 : 0;
        }
    }           
}

${$day}[...] instead of $$day[..], because PHP cannot determine if you want the name of the variable to be $day or $day[..] — nice ass
"I believe the problem is my use of variable variables" - well, use of variable variables is always a problem, in my opinion. Why do you not use an associative array instead, just like you have for $hours? — IMSoP
@onetrickpony - perfect... that is working as expected and makes sense now that I see it. — user756659
Other things to improve your readability: in_array() returns boolean so you don't need that == 1; the 24 incredibly similar lines of code should be turned into a loop, as should the last seven calls to file_put_contents (easy if you have an associative array: you can just use foreach); if you have control of the data format, use the 24-hour clock rather than all those slightly incompatible hour labels. Oh, and print_r is not a good format for saving, because it isn't designed to be read back as data; try var_export or serialize, or perhaps json_encode — IMSoP
@IMSoP - What were you thinking? $hours could be empty or only contain values for a few days or all of course. Every way I can think of would still require a way to know the actual day. — user756659

nice ass nice ass · Accepted Answer · 2014-03-22T16:03:18

I would restructure that code like this:

// keys; you can also use a for() loop to generate them
$hourDefs = array('12am', '1am', '2am' ... );  
$output = array();

foreach($weekdays as $day){
  if(!isset($hours[$day]))
    continue;

  // store the output inside an array so you can loop it later
  foreach($hourDefs as $def)
    $output[$day][$def] = in_array($def, $hours[$day]) == 1 ? 1 : 0;

}

foreach($output as $name => $data){
  $pathName = sprintf('/home/test/public_html/file-%s.txt', $name);
  file_put_contents($pathName, print_r($data, true));
}

If you want to keep the inconsistency between key names use substr($def, 0, -1) on $output

php and variable variables with array

1 Answers