Adding numbers doesn't give expected results

Question

I have 3 numbers returned from a database that I need to add together. For a total of 1,740.01, I get like 10.00. These are floating point numbers. Here are the actual numbers I'm having a problem with.

> 1,729.13 > 10.88 > 0.00

How do I get the correct total of these numbers?

EDIT

$cash = preg_replace('/\$/', '', $cash); $card = preg_replace('/\$/', '', $card); $check = preg_replace('/\$/', '', $check); $cash = number_format(array_sum($cash), 2); $card = number_format(array_sum($card), 2); $check = number_format(array_sum($check), 2); $total = number_format( $cash + $card + $check, 2 );

The total is 1,740.01, in case you're wondering. If you need more, it'd be delightful to see the code you're using, so we can help fix it. — Sebastian Paaske Tørholm
– Sebastian Paaske Tørholm, Commented Jan 30, 2011 at 12:22
possible duplicate of PHP Math Precision, Rounding in PHP, How to fix this problem in PHP? — outis
– outis, Commented Jan 30, 2011 at 12:23
@jim, see stackoverflow.com/posts/4842845/revisions for what happened to your original number. — sarnold
– sarnold, Commented Jan 30, 2011 at 12:28

Mark Baker · Accepted Answer · 2011-01-30 13:38:26Z

Don't add values that have been formatted using number_format(), otherwise they may well contain , as a thousand's separator... they're treated as strings rather than floats.

Assuming that $cash, $card and $check are arrays:

$cash = array_sum($cash); $card = array_sum($card); $check = array_sum($check); $total = number_format( $cash + $card + $check, 2 ); $cash = number_format( $cash, 2 ); $card = number_format( $card, 2 ); $check = number_format( $check, 2 );

Do any formatting after the math

EDIT

Use str_replace() rather than preg_replace() to strip out any $, then it's simple addition rather than needing to do the array_sum(), though I'm not sure where any $ is likely to come from if the values are DECIMAL 10,7 from the database

$cash = (float) str_replace( array('$',','), '', $cash ); $card = (float) str_replace( array('$',','), '', $card ); $check = (float) str_replace( array('$',','), '', $check ); $total = number_format( $cash + $card + $check, 2 ); $cash = number_format( $cash, 2 ); $card = number_format( $card, 2 ); $check = number_format( $check, 2 );

(assumes that , is your thousands separator in the string values for $cash, $card and $check when doing the str_replace()

EDIT 2

To convert the $cash array to a sum of its values, having cleaned up any $ or , in the strings:

$cash = array ( 0 => '$1729.13', 1 => '0.00', 2 => '$1,234.56' ); function cleanArrayValues($value) { return (float) str_replace( array('$',','), '', $value ); } $cash = array_sum(array_map('cleanArrayValues',$cash));

I've added an extra value into the $cash array just to demonstrate.

You'll need to filter $card and $checks in the same way, using the cleanArrayValues() callback function (if they're all arrays)

Thanks Mark, just answered you above. The variables are arrays from pref_replace. So you're saying that I need to add these numbers together and then use number_format?
Just make sure they're numbers not strings. A , in 1,729.13 makes PHP cast the entire number to 1.
@Mark, thanks. These are values that I'm using elsewhere in my code so I needed to strip off the dollar sign. Thanks for the edit and example. I'll give this a shot now.
@Jim - If it's the same problem, then edit your original post here, else raise it as another question

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