在 PHP 中为变量分配数值

Question

I am trying to assign a variable the value of 01234 using PHP. But it keeps coming up with a different number. Why is it is displaying 668 ?

$data = 01234;
echo $data;

The result I am getting is: 668

Answer 1

From the manual :

Integers can be specified in decimal (base 10), hexadecimal (base 16), octal (base 8) or binary (base 2) notation, optionally preceded by a sign (- or +).

[...]

To use octal notation, precede the number with a 0 (zero) . To use hexadecimal notation precede the number with 0x. To use binary notation precede the number with 0b.

You mistakenly specified the octal number 1234 (by adding the zero prefix) which equals 668 decimal.

Answer 2

Having a leading zero is an instruction to parse it as an octal number, As having 0x as prefix means hex. See the documentation for more information .

So this 01234 is parsed as octal and converted to decimal value which is 668.