Converting binary string to IEEE 754 float

Question

Can someone tell me how to convert a 32-bit binary string to an IEEE 754 floating point value in Ruby?

For example, the binary string "01000001100101110011001100110011" (0x41973333) should convert to 18.9, but I can't figure out how to do this using Ruby.

I'm trying to get the same values returned by: https://www.h-schmidt.net/FloatConverter/IEEE754.html

Thanks.

Eric Duminil · Accepted Answer · 2017-01-08 21:58:18Z

5

That was a fun one!

You need String#unpack and Array#pack :

["01000001100101110011001100110011"].pack('B*').unpack('g').first
#=> 18.899999618530273
[18.9].pack('g').unpack('B*').first
#=> "01000001100101110011001100110011"

'g' is :

 g         | Float   | single-precision, network (big-endian) byte order

'B*' is multiple :

B         | String  | bit string (MSB first)

edited Jan 8, 2017 at 21:58

answered Jan 8, 2017 at 21:49

Eric Duminil

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1 Comment

user3481798 Over a year ago

Thank you so much!!

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