PHP 在字符串中显示浮点数

Question

I want to show a float number in php string.

something like:

My float number is: 0.00003485

But when I am using echo I see it like this:

My float number is: 3.485E-5

Also, I know I can use printf("%.10f",$float) code, but I need to use it in lots of places in my string, So I can't use printf .

What code should I use on a string, to show floats as they are? I don't want that shorted number (3.485E-5).

Answer 1

At some condition i am prefer declaration float number as string:

MyFloatNumber = "0.0000000000000000000000003485";

so,

echo MyFlatNumber; //0.0000000000000000000000003485

Answer 2

I know I can use printf("%.10f",$float) code, but I need to use it in lots of places in my string, So I can't use printf.

I have to respectfully disagree with that:

printf('My float number is: %1$.8f (again: %1$.8f; once more: %1$.8f)', 0.00003485);

Or, if you need it in a string:

$foo = sprintf('My float number is: %1$.8f (again: %1$.8f; once more: %1$.8f)', 0.00003485);

Of course, if you mean it's against project style guidelines or company policy, that's another story.

What code should I use on a string, to show floats as they are?

Really? Floats in PHP are a 64-bit IEEE 754 double precision format bitmap. According to this online converter , number 0.00003485 would be:

0010010001010111110011100001110100101110111001001111

Of course, they aren't actual ones and zeroes but different voltage levels ;-)

Answer 3

You can write a function to handle this in any way you want. Why not?

function fval($f, $precision = 9) { 
    return number_format($f, $precision); 
}

Then any place you need to format, call it out:

$f = 3.485E-5;
echo fval($f);  // this will print: 0.000003485