Solved

newbie needs help

Posted on 2004-04-09
2
180 Views
Last Modified: 2010-03-04
Hello experts,

I just start with perl language few days ago.  I need to know what does the & symbol means in the folowing script:

#!/usr/bin/perl
                                                                                                                             

push @array, (1,2,3)[6 & 10];
                                                                                                                             
                                                                                                                             
print @array;

------------------
result: 3

-------------------
what I know that the push function pushes the values of list onto the end of array.  ANd number in square bracets point to list index .   Can somebody give me a hint.

thanks

luxana
0
Comment
Question by:Luxana
2 Comments
 
LVL 8

Accepted Solution

by:
davorg earned 30 total points
ID: 10789957
& is the "bitwise and" operator. It compares the binary representation of two numbers and returns the number that has bits set only where the same bit is set in _both_ of the input numbers.

So, in your example:

6 is 0110 in binary.
10 is 1010 in binary.

They only have one bit in common, so a bitwise and opertion returns 0010. Converting that to decimal gives 2.

So 6 & 10 is 2.

Your code therefore becomes:

push @array, (1,2,3)[2];
                                                                             
print @array;

Which has the same effect as:

push @array, 3;

There is also a "bitwise or" operator which returns a set bit where either of the inputs have a set bit. 6 | 2 is 1110 (which is 14) and a "bitwise exclusive or" which returns a set bit where only on of the inputs have a set bit. 6 ^ 2 is 1100 (which is 12).

See "perldoc perlop" for more details.

Dave...
0
 
LVL 10

Author Comment

by:Luxana
ID: 10790190
Dave ,

I got it:))) You have no idea how many things I tried. Perfect so now I can move on:)))

Thanks for your help Dave

LUXANA

0

Featured Post

Find Ransomware Secrets With All-Source Analysis

Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

Join & Write a Comment

Email validation in proper way is  very important validation required in any web pages. This code is self explainable except that Regular Expression which I used for pattern matching. I originally published as a thread on my website : http://www…
There are many situations when we need to display the data in sorted order. For example: Student details by name or by rank or by total marks etc. If you are working on data driven based projects then you will use sorting techniques very frequently.…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

26 Experts available now in Live!

Get 1:1 Help Now