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Get each bit from a number

hem
User

Sep 6, 2012, 9:06 AM

Post #1 of 4 (1332 views)

Get each bit from a number	Can't Post

Hello

I have a 16 bit number and I have to extract each bit from that number . Each bit has a meaning and I have to run an if loop on every bit i get.

How can i extract each bit from a number in Perl

Thanks in advance

FishMonger
Veteran

Sep 6, 2012, 9:22 AM

Post #2 of 4 (1330 views)

Re: [hem] Get each bit from a number [In reply to]	Can't Post

Use the sprintf function to convert the number to binary then use either the split or substr or unpack function to access each bit.

BillKSmith
Veteran

Sep 6, 2012, 3:39 PM

Post #3 of 4 (1309 views)

Re: [hem] Get each bit from a number [In reply to]	Can't Post

I find it difficult to get all the details right using the procedure that FishMonger outlined. The data structure that you describe is a bit-vector, not a number. You may be able to exploit this by using the built-in function vec. (Refer: perldoc -f vec) to both set and read the bits.
Good Luck,
Bill

hem
User

Sep 8, 2012, 12:06 PM

Post #4 of 4 (1264 views)

Re: [BillKSmith] Get each bit from a number [In reply to]	Can't Post

Hi Guys

Thanks for your help. I used your advice and did the following.

Appreciate your help and time . Thanks a ton

Code

my $firstVar = 19; 
$firstVar = unpack("B32", pack("n", $firstVar)); 
my $First =  substr($firstVar,-1,1);   #to get the last bit

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