[wp-hackers] $wpdb->prepare and %d for integers

[Dion Hulse (dd32)]

Also created http://core.trac.wordpress.org/ticket/18407 to clarify
the WPDB Docs that calls %d a decimal is infact, an integer.

On 15 August 2011 11:53, Dion Hulse (dd32) <wordpress at dd32.id.au> wrote:
> Quite simply, %d treats the value as a Integer. Integers in PHP do not
> contain commas, 0-9 are the expected values. PHP's internal
> String->Integer parsing code uses the first 0-9. segment of the number
> as the final value.
>
> Eg:
> $in = '123,456.789';
> printf('%d', $in); //123
> var_dump( (int)$in ); //123
>
> $in = '123456.789';
> printf('%d', $in); //123456
> var_dump( (int)$in ); //123456
>
> The PHP documentation does indeed specify, that %d is a decimal.. but
> that's just not the case.. It's an Integer.
>
> PHP's closest thing to a Decimal is the Float data type:
> $in = '123456.789'; // Note: commas will return 123 again.
>
> printf('%f', $in); //123456.789000
> var_dump( (float)$in ); //float 123456.789
>
> the WPDB Class only specifies %s and %d as valid placeholders, but i
> don't see any code which restricts it to that, so you might be able to
> use %f to represent decimals (as floats, which remember, are less
> accurate than a decimal)
>
> On 15 August 2011 11:36, 24/7 <24-7 at gmx.net> wrote:
>> As to the description of the *%d type specifier* for *sprintf* in the php
>> manual <http://php.net/manual/en/function.sprintf.php>, *%d* should be "*d -
>> the argument is treated as an integer, and presented as a (signed) decimal
>> number.*". I run into the problem that using *$wpdb->update* along with the
>> *$format* and *%d* removed all values behind the comma (or "ceiled" them?).
>> It took me ages to find that problem and so I had to insert strings into *double
>> *columns as a work around.
>>
>> I wanted to open a ticket about that, but I couldn't really get behind the
>> reason why this happens (and ran out of time). Is there anyone who knows
>> what exactly is responsible for this behavior - as this is (imo) a bug?
>>
>> Best wishes,
>> K.
>>
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>