php - printf and sprintf have different outputs

Question

I written the following tiny php program to test printf and sprintf:

<?php
    $str_1 = printf("%x%x%x", 65, 127, 245);
    $str_2 = sprintf("%x%x%x", 65, 127, 245);

    echo $str_1 . "\n";
    echo $str_2 . "\n";

the output is this:

417ff56
417ff5

why I have that 6 digit in the first line of output?

your $str_1 contains a "6" - length returned by printf — vp_arth
– vp_arth, Commented Nov 25, 2014 at 7:14

MwamiTovi · Accepted Answer · 2023-05-14 09:53:29Z

9

printf doesnt return the string, it directly outputs it (and returns only its length). Try this

<?php
    printf("%x%x%x", 65, 127, 245);
    $str_2 = sprintf("%x%x%x", 65, 127, 245);
    echo "\n". $str_2 . "\n";
?>

Output

417ff5
417ff5

Now you might ask why that extra 6 (in your output) then? Becuase printf returns the length of the printed string which is 6 in your case.

So here is how it goes

417ff56            // that extra 6 comes from your first echo.
417ff5

MwamiTovi

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answered Nov 25, 2014 at 7:13

Hanky Panky

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Comments

Rakesh Sharma · Accepted Answer · 2014-11-25 07:18:36Z

0

printf :- directly print the formatted string.

sprintf :- convert given format and store values in a variable and you can use echo/print to print variable values.

$text = "65 127 245";
printf("%x%x%x", 65, 127, 245);
$str_2 = sprintf("%x%x%x", 65, 127, 245);
echo $str_2;

answered Nov 25, 2014 at 7:18

Rakesh Sharma

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