How do I determine multi-select combinations in php
Question
I am having 3 SELECT elements such as "province", "district" and "market" in my HTML code. I need a sample algorithm to detect the combination on which form elements a selection has been done or not. I am thinking about 6 combinations of if conditions.
How can I determine the combination of filled SELECT elements with a minimum number of if conditions?
My code so far should illustrate, what I am trying to achieve:
<select name="a">
<option value="acity">a city</option>
</select>
<select name="b">
<option value="bdistrict">b district</option>
</select>
<select name="c">
<option value="cmarket">c market</option>
</select>
<?php
if($_POST["a"] != null and $_POST["b"] != null and $_POST["c"] != null)
echo "aaaa";
elseif($_POST["a"] != null and $_POST["b"] != null)
echo "bbb";
/*elseif ...*/
?>
Thanks for reply.
1 answers
solution1
0 ACCPTED 2016-05-04 04:38:08
You can store the answers in an array. The code below does 2 decisions: How many consecutive options from the first one has been selected and any combination inclusive none. Instead of storing values you could even store functions.
$combination = [ 'abc' => function() {return 'foo bar';} /* , ... */ ];
$combination['abc']();`
<!DOCTYPE html>
<html>
<body>
<form method="post">
<select name="a">
<option></option>
<option value="acity">a city</option>
</select>
<select name="b">
<option></option>
<option value="bdistrict">b district</option>
</select>
<select name="c">
<option></option>
<option value="cmarket">c market</option>
</select>
<button type="submit">submit</button>
</form>
<?php
$post_keys = [
'a' => 'aaa',
'b' => 'bbb',
'c' => 'ccc'
];
$value = '[no valid selection]';
foreach($post_keys as $key => $val)
if(isset($_POST[$key]) && '' !== $_POST[$key])
$value = $val;
else
break;
?>
<div>Form has been filled until: <?php echo $value;?>.</div>
<?
$combination = [
'' => 'nothing',
'a' => 'only a',
'ab' => 'c missing',
'abc' => 'all',
'ac' => 'b missing',
'b' => 'only b',
'bc' => 'a missing',
'c' => 'only c'
];
$key_seq = '';
foreach($post_keys as $key => $val)
if(isset($_POST[$key]) && '' !== $_POST[$key])
$key_seq .= $key;
$value = $combination[$key_seq];
?>
<div>Combination of a,b,c: <?php echo $value;?>.</div>
</body>
</html>
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