在PHP中将二进制文件数据转换为浮点数据

Question

I would like to store floating point numbers in a SQL blob record and then read in the data as floating point numbers. I am not sure this is possible and I have not been able to make the conversion on my own.

For example, suppose I read in the string data "3f000000" . This 4-byte interpreted as an IEEE-754 floating point number would 0.5.
I would like to make this conversion in PHP. I tried using $n = floatval(hexdec('3f000000')) but that just returns an integer number. Could someone help me with this please?
Also, $n=floatval('0x3f000000') just returns 0.

Answer 1

are you sure that "3f000000" is realy 0.5 ?

it try this :

var_dump(unpack("f", pack("H*", "3F000000"))); // give 8.82...E-44
var_dump(unpack("f", pack("H*", "0000003F"))); // give 0.5