Convert string to integer (binary)

Posted on 2003-12-09
Last Modified: 2012-05-04
I have a 4 byte string which I would like to convert to a integer. I'm reading the data from a file and the file contains 4 bytes for the ID number. So I've extracted the 4 bytes as text into a variable, but I want to print it's value as an integer.

And I don't only want to print it, I'd like to actually have a variable which contains the data as an integer, so that I can work with it.

Question by:dankennedy
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LVL 24

Expert Comment

Comment Utility
like u have a string called '123' and 123 number.

LVL 24

Expert Comment

Comment Utility
like u have $string called '1234'. u want it to convert $int which is a int.


$int = 0+ $string
print "$int \n";
and now u can work with this variable $int which is an integer.

Author Comment

Comment Utility

I'm reading 4 bytes from a file.

Binary: 00000000 00000000 00000000 01000000

So when I read it into Perl, it's represented as a string...

String: '\0\0\0@'

But I want it to be represented as an integer..

Integer: 64

So I need code that will take a 4 byte string and give me it's integer value...
LVL 24

Accepted Solution

shivsa earned 250 total points
Comment Utility
try pack and unpack functions of perl.

Author Comment

Comment Utility

Here's how it works for anyone else who's wondering...

use the function unpack.

$myint = unpack("N",$mystring);

or for little endian...

$myint = unpack("V",$mystring);

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