from the sum of selected values how to find which days are selected

Question

I have a list of checkboxes with weekdays name and those values are [1,2,4,8,16,32,64]

<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="1" id="check_sun"/>Sunday<span></span>
</label>
<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="2" id="check_mon"/>Monday<span></span>
</label>
<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="4" id="check_tue"/>Tuesday<span></span>
</label>

<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="8" id="check_wed"/>Wednesday<span></span>
</label>
<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="16" id="check_thu"/>Thursday<span></span>
</label>
<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="32" id="check_fri"/> Friday<span></span>
</label>
<label class="m-checkbox">
    <input type="checkbox" name="selected_days[]" value="64" id="check_sat"/> Saturday<span></span>
</label>

While saving them I make a sum of selected checkboxes to store in DB

<?php array_sum($post_data["selected_days"]);?>

So the problem is while getting the day I get some of the select checkboxes right. I am unable to find how to display selected checkboxes with the sum

Ex: Mon, Tue and Sat selected So the DB value will be 70 (2+4+64) When I get from DB it will be 70. How do I know those are Mon, Tue & Sat only

Please help me to do it

Possible duplicate of [Check if checkbox is checked with jQuery](https://stackoverflow.com/questions/2204250/check-if-checkbox-is-checked-with-jquery) — Mohammad Malek, Mar 11 '19 at 05:59
@Ashu I have to save sum only, that is must please tell me how get days from that sum — , Mar 11 '19 at 06:03
@DeviG you are successfully getting selected check box sum & storing into db right? — Ashu, Mar 11 '19 at 06:07
@Ashu Yes.. I want to display from that sum, which checkboxes are selected — , Mar 11 '19 at 06:15
@SruthiG then defiantly you have to store days in db..There is no any other option to get the days from total — Ashu, Mar 11 '19 at 06:17

balakrishnan · Answer 1 · 2019-03-11T06:18:51.360

You can do it by using bit wise operators

DB Sum Column & Input Day = Input Day
70 & 4 = 4
70 & 2 = 2
70 & 64 = 64

For other days the value will be 0.

Update

$daysArr = [1=>'Sunday', 2=>'Monday', 4=>'Tuesday', 8=>'Wednesday', 16 => 'Thursday', 32=>'Friday', 64=>'Saturday'];
$selectedArr = [];
$dbData = 70; //Your db result here
foreach($daysArr as $selDay => $selDayName)
{
    if($dbData & $selDay){
        $selectedArr[] = $selDay;
    }
}

print_r($selectedArr);

PHP code to check this for dynamic values.

Twista · Answer 2 · 2019-03-11T07:19:42.293

1

$sum = 29;
$days = array("Sun","Mon","Tue","Wed","Thur","Fri","Sat");
$selected = str_split(decbin($sum));
$count = count($selected);
echo "Checked days are "; 
for($i=0;$i<=$count-1;$i++){
    if($selected[$i]==1){
    echo $days[$i] ." ";
    }
}

edited Mar 11 '19 at 07:19

answered Mar 11 '19 at 06:56

Twista

241
3
11

Can't use this method when you consider "Sunday" as starting day. – balakrishnan Mar 11 '19 at 07:17
Yep, It's a matter of rearranging the $days array.I dont know why I put them in that order. Will edit – Twista Mar 11 '19 at 07:19
Making `$selected = str_split(strrev(decbin($sum)));` makes the code work with "Sunday" as start day and works with the given values as per the question. – balakrishnan Mar 11 '19 at 07:42

from the sum of selected values how to find which days are selected

2 Answers2