PHP printf function and it's weird behaviour

Question

I\'m baffled what these numbers mean. To me it seems that printf gives me wrong results.

echo printf(\"%.2f\", 1);
// 1.004

echo printf(\"%.3f\", 1);
// 1.0         


        

Answer 1

Simple. printf() has a return value, which is integer. And that value is - length of resulting string. Thus, your code is doing two things:

• First, format & output your string with printf()
• Second, echo() the result, which is the length for each string.

That is because you see 1.004 for first case, for example. It's 1.00 with 4 (and length of "1.00" string is 4)

If your intention is to print formatted string, either use printf() as it is:

printf("%.2f", 1);

Or use sprintf() with echo:

echo sprintf("%.2f", 1);