Solved

Getting confused with 2d arrays

Posted on 2008-06-11
6
142 Views
Last Modified: 2011-09-20
Hi,

I just built a 2D array, and I want to iterate over all elements for printing. I tried this:

for ($i = 0; $i < @rows; $i++) {
    for ($j = 0; $j < @rows[$i]; $j++) {
        print($rows[$i][$j], "  ");  
    }
    print("\n");
}

where @rows is my 2D array, but the script just executes in an infinite loop. I'm guessing the problem is:

      $j < @rows[$i]

in that statement I mean to say the length of the 1d array in element $i of the 2D array. What's the right syntax for it?

thanks
0
Comment
Question by:DJ_AM_Juicebox
6 Comments
 
LVL 39

Expert Comment

by:Adam314
ID: 21761331

for(my $i = 0; $i < @rows; $i++) {

	for (my $j = 0; $j < @{$rows[$i]}; $j++) {

		print($rows[$i][$j], "  ");  

	}

	print("\n");

}

Open in new window

0
 
LVL 13

Expert Comment

by:marchent
ID: 21761414
Here you'll find how to iterate the 2d array with example http://icfun.blogspot.com/2008/03/perl-two-dimensional-array-handling.html
0
 

Author Comment

by:DJ_AM_Juicebox
ID: 21762045
Ehh still seems to just loop endlessly. Here's my entire script:




my @rows = ( [2, 4, 6],
             [3, 6, 9],
           );

for (my $i = 0; $i < @rows; $i++) {
    for (my $j = 0; $j < @{rows[$i]}; $j++) {
        print($rows[$i][$j], "  ");  
    }
}
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 39

Accepted Solution

by:
Adam314 earned 500 total points
ID: 21762470
You are missing the $ in front of rows[$i].  It should be:
The @{$rows[$i]} means:
    take $rows[$i], which is a reference to an array
    Then take that array

Then the $j < mean interpret that array in scalar context, which means return the number of elements in the array.
my @rows = ( [2, 4, 6],

             [3, 6, 9],

           );
 

for (my $i = 0; $i < @rows; $i++) {

    for (my $j = 0; $j < @{$rows[$i]}; $j++) {

        print($rows[$i][$j], "  ");  

    }

}

Open in new window

0
 

Author Comment

by:DJ_AM_Juicebox
ID: 21763025
ok you're right, thanks.
0
 
LVL 84

Expert Comment

by:ozo
ID: 21763984
It may be safer to itterate
for my $i( $[ .. $#rows ){ for my $j ( $[ .. $#{$rows[$i]} )
Or a simpler way is
print "@$_\n" for @rows;
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A year or so back I was asked to have a play with MongoDB; within half an hour I had downloaded (http://www.mongodb.org/downloads),  installed and started the daemon, and had a console window open. After an hour or two of playing at the command …
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…
This is a video that shows how the OnPage alerts system integrates into ConnectWise, how a trigger is set, how a page is sent via the trigger, and how the SENT, DELIVERED, READ & REPLIED receipts get entered into the internal tab of the ConnectWise …

930 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

16 Experts available now in Live!

Get 1:1 Help Now