arrays - How can I change a PHP variable with an input form? -


i have sets of arrays each have value attributed them. value goes through function find percentage displayed on page. here's snippet of code:

<?php $balls = array(     'blue' => 4,     'red' => 13,     'green' => 5 );  function percent($array, $element) {     $total = array_sum($array);     $elementvalue = $array[$element];     return ($elementvalue / $total) * 100; } ?>  <html> <body> blue balls per set:<?php echo $balls["blue"]; ?>. percentage of blue balls:<?php echo percent($balls, 'blue'); ?>%. </body> </html>

how add input form change equation around. specifically, want able add variable ($sets) multiply values of array items before summed up.

the closest thing can think of this:

$sets = value input form, if no value entered, default 1  $balls = array(     'blue' => 4 * $sets,     'red' => 13 * $sets,     'green' => 5 * $sets );

the rest of equation work usual, updated new value $sets submitted in input form. also, such thing update numbers displayed on webpage instantly?

if $sets thing you're interested in changing, can set small html form (assuming index.php name of php file):

<form action="index.php" method="post">  number of sets: <input type="text" name="sets" />  <br /><input type="submit" value="get sum!" /> </form>

in php code, can following value when submits html form:

$sets = 1; // default value  // make sure value sent if(isset($_post['sets'])) {     // check sets numeric, , above 0     if(is_numeric($_post['sets']) && $_post['sets'] > 0) {         $sets = $_post['sets'];     } }  // computation $sets...

yes, if send value html form php page, values on page according sent in form immediately.

it looks you're starting php (or programming in general) – best of luck! 1 important rule remember validate user input, did here: we've checked sent number (as that's require) , value bigger 0.

we've added value of $_post['sets'] our variable once sure met our criteria. never know people might try send , want prepared case.

setting $sets 1 in beginning means we're starting default value , can worry setting $sets else when want to. consider in contrast:

if(isset($_post['sets'])) {     if(is_numeric($_post['sets']) && $_post['sets'] > 0) {         $sets = $_post['sets'];     }     else {         $sets = 1;     } } else {     $sets = 1; }

this less nice because less obvious $sets will, positively, have valid value in given case. means need change 1 number if decide change default value.

this rather trivial in example since code small, i'm sure can imagine benefit once write bigger code more complex checks.


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