Show a percentage based on values from a table

[AndyJones]

Hi there,

I have inherited a site, and am not very good with PHP so please forgive me!

It's a simpel voting system, where people vote for A B or C.

I have the following php on a page, which looks in a table, pulls the 'total' for each row (vote) and displays then on a page so we can see how many votes were given to A, B or C.

<?php
$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
$stmt->execute();
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
$output = [];

foreach ($rows as $row) {
    $output[] = $row['option'] . ' has ' . $row['total'] . ' votes';
}

return implode('<br><br>', $output);

So the ooutut is currently:

 

A has 10 votes

B has 30 votes

C has 40 votes

 

 

I would like to be able to put a percentage next to each number of 'votes' - so that the user can see the percentage of all the votes so far.

e.g.

A has 10 votes (12.5%).

B has 30 votes (37.5%).

C has 40 votes (50%).

I hope the above makes sense!

Thanks in advance for a steer in the rirght direction - I just don't know PHP well enough to work out the syntax etc.

 

[mac_gyver]

what value do you need to calculate the percentage, the total number of votes? you just need to devise a method of getting that value from the fetched data in $rows. one method would be to loop over the data to add up the individual totals. another method would be to use php's array functions to operate on the data as a set - see php's array_column() and array_sum().

[ginerjm]

How about this?

$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
if ($stmt->execute())
{
	$sum = 0;
	$output = array();
	while($row == $stmt->fetch(PDO::FETCH__ASSOC))
	{
		$sum += $row['total'];
		$output[] = $row;
	}
	foreach ($output as $line)
	{
		$pct = number_format(($line['total'] / $sum)*100, 2);
		echo $line['option'] . ' has ' . $line['total'] . " votes (%$pct)<br><br>";
	}
}
else
	echo "Query did not execute";

Did not test.

[ginerjm]

Oops.  youll have to play with the % sign.  I put it in the wrong place.

" votes (" . $pct .  "%)<br><br>";

 

[Barand]

or...

$res = $pdo->query("SELECT `option`, total FROM vote");
$data = $res->fetchAll();
$votes_cast = array_sum( array_column($data, 'total') );
foreach ($data as $r) {
    printf ("%s has %d votes (%0.1f %%)<br>", $r['option'], $r['total'], $r['total']*100/$votes_cast);
}          

 

[AndyJones]

On 6/9/2022 at 5:51 PM, ginerjm said:

Oops.  youll have to play with the % sign.  I put it in the wrong place.

" votes (" . $pct .  "%)<br><br>";

 

Thanks for this - I'll have a play aroudn with it in the morning!

Will report back!

 

Andy

[AndyJones]

On 6/9/2022 at 7:45 PM, Barand said:

or...

$res = $pdo->query("SELECT `option`, total FROM vote");
$data = $res->fetchAll();
$votes_cast = array_sum( array_column($data, 'total') );
foreach ($data as $r) {
    printf ("%s has %d votes (%0.1f %%)<br>", $r['option'], $r['total'], $r['total']*100/$votes_cast);
}          

 

Ah thanks - will have a play with this too.

 

Thanks for your input and advice!

[AndyJones]

On 6/9/2022 at 5:41 PM, ginerjm said:

->

 

On 6/9/2022 at 5:41 PM, ginerjm said:

How about this?

$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
if ($stmt->execute())
{
	$sum = 0;
	$output = array();
	while($row == $stmt->fetch(PDO::FETCH__ASSOC))
	{
		$sum += $row['total'];
		$output[] = $row;
	}
	foreach ($output as $line)
	{
		$pct = number_format(($line['total'] / $sum)*100, 2);
		echo $line['option'] . ' has ' . $line['total'] . " votes (%$pct)<br><br>";
	}
}
else
	echo "Query did not execute";

Did not test.

So I tried your solution but it throws a 500 internal server error?

I've played aroudn, but I can't get it working. Any ideas?

This is what I used:

$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
if ($stmt->execute())
{
	$sum = 0;
	$output = array();
	while($row == $stmt->fetch(PDO::FETCH__ASSOC))
	{
		$sum += $row['total'];
		$output[] = $row;
	}
	foreach ($output as $line)
	{
		$pct = number_format(($line['total'] / $sum)*100, 2);
		echo $line['option'] . ' has ' . $line['total'] . " votes (" . $pct .  "%)<br><br>";
	}
}
else
	echo "Query did not execute";

 

[AndyJones]

On 6/9/2022 at 7:45 PM, Barand said:

or...

$res = $pdo->query("SELECT `option`, total FROM vote");
$data = $res->fetchAll();
$votes_cast = array_sum( array_column($data, 'total') );
foreach ($data as $r) {
    printf ("%s has %d votes (%0.1f %%)<br>", $r['option'], $r['total'], $r['total']*100/$votes_cast);
}          

 

So I just had a play with this - but I don't really understand what to to do with your code at all - it doesn't resemble mine enough to know what to replace.

[ginerjm]

The error in my code is the double equal in the whille line.

As for Barand's code, just run it and see what it gives you.

[Barand]

7 minutes ago, AndyJones said:

but I don't really understand what to to do with your code at all

RTFM

• https://php.net/array_sum
• https://php.net/array_column
• https://php.net/printf

 

[AndyJones]

10 hours ago, ginerjm said:

The error in my code is the double equal in the whille line.

As for Barand's code, just run it and see what it gives you.

Thank you. I changed the double Eqaals to a single, but it's still showing a 500 server error.

I ran Barand's code, but it doesn't connect to the database table - so wondering if it was supposed to go with some of the existing code.

This is what I have now:

 

<?php
$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
if ($stmt->execute())
{
	$sum = 0;
	$output = array();
	while($row = $stmt->fetch(PDO::FETCH__ASSOC))
	{
		$sum += $row['total'];
		$output[] = $row;
	}
	foreach ($output as $line)
	{
		$pct = number_format(($line['total'] / $sum)*100, 2);
		echo $line['option'] . ' has ' . $line['total'] . " votes (" . $pct .  "%)<br><br>";
	}
}
else
	echo "Query did not execute";
	

 

10 hours ago, Barand said:

RTFM

• https://php.net/array_sum
• https://php.net/array_column
• https://php.net/printf

 

I think that was a bit harsh to be fair - as I said I've picked this up to help someone out, and I don't know PHP. It would be a huge learning curve and would take many hours of learning to figure this out - when I'm just trying to help someone out - hence why I came here for advice.

 

[Barand]

1 hour ago, AndyJones said:

$stmt = $modx->prepare("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");

 

On 6/9/2022 at 7:45 PM, Barand said:

$res = $pdo->query("SELECT `option`, total FROM vote");

@AndyJones If you compare the above 2 lines you will see that my PDO connection is $pdo whereas yours is $modx.

Just change my $pdo to $modx to use your connection.

[AndyJones]

59 minutes ago, Barand said:

 

@AndyJones If you compare the above 2 lines you will see that my PDO connection is $pdo whereas yours is $modx.

Just change my $pdo to $modx to use your connection.

Ahah - bingo - thank you so much!

Thjis is the final code that works:

<?php
$res = $modx->query("SELECT * FROM `modx_ltda_vote` ORDER BY `option` ASC");
$data = $res->fetchAll();
$votes_cast = array_sum( array_column($data, 'total') );
foreach ($data as $r) {
    printf ("%s has %d votes (%0.1f %%)<br>", $r['option'], $r['total'], $r['total']*100/$votes_cast);
}          

Thanks again _ will endevor to learn this stuff - but just needed a quick help out as it's something I need to get live for a friend.

Cheers

Andy

[mac_gyver]

the last issue above, the mismatched variable names, would have been producing php errors. is php's error_reporting set to E_ALL and display_errors set to ON, preferably in the php.ini on your system, so that php would help you by reporting and displaying all the errors it detects?

Edited June 15, 2022 by mac_gyver

[AndyJones]

Just now, mac_gyver said:

that last issue above, the mismatched variable names, would have been producing php errors. is php's error_reporting set to E_ALL and display_errors set to ON, preferably in the php.ini on your system, so that php would help you by reporting and displaying all the errors it detects?

Hmm OK - I'll go check. Thanks.

[ginerjm]

Simply add these 2 lines to the top of your scripts while you are developing them:

error_reporting(E_ALL);
ini_set('display_errors', '1');

To turn off change the '1' to '0'.

[AndyJones]

15 minutes ago, ginerjm said:

Simply add these 2 lines to the top of your scripts while you are developing them:

error_reporting(E_ALL);
ini_set('display_errors', '1');

To turn off change the '1' to '0'.

Ah handy - thanks!