Reading file names into perl and adding to their names

[djnsh]

My problem, although appearing simple on the surface, does not seem as straight forward as I first thought.

I have a directory containing files, with each file having the same start such as apples_45.4554-34, apples_56.4554-34, and so on. There are hundreds like this which I generated using another perl program.

The same directory also contains similar file names, however different starting positions such as bananas_45.4554-34, bananas_56.4554-34.

What I am trying to do is merge the two files together which have the same end to produces an output file such as one called oranges_45.4554-34 which contains the contents of both apples_45.4554-34 and bananas_45.4554-34.

I can do the bringing together bit as I have tried it on one example when I specified the complete file name of each of the two components like in my example above, however I cannot work out how to do it automatically for every file with the apples_* and bananas_* start for every end without specifing each file separately which is impossible.

Help!

 

[chazoid]

I should leave this for the more clever programmers here, but since no one has replied yet, this might get you started..

@files = glob("*.*");

foreach $fileName (@files){ 
    
    ($leftSide,$rightSide) = split("_",$fileName);
    
    push (@arrRightSide,$rightSide);
}

# from Effective Perl Programming:
@arrRightSide = sort keys %{ { map { $_, 1 } @arrRightSide } };

the last line will eliminate any duplicates from @arrRightSide, then you could loop through it and use pattern matching to grab the files that you want to combine.
There's probably a simple way to do this, but you're right.. it's trickier than it sounds. If I get a chance, I'll see if I can finish this..

-jt

 

[133tcamel]

my $some_dir = '/home/dir/';
opendir(DIR, $some_dir) || die "can't opendir $some_dir: $!";
my @files = grep { /^apple/ && -f "$some_dir/$_" } readdir(DIR);
closedir DIR;

for my $file1 (@files)
{
  (my $file2 = $file1) =~ s/^apple/banana/;

  #now you have both the file names ("$some_dir/$file1" & "$some_dir/$file2"), so concat them here...
}

---
cheers!
san

"The universe has been expanding, and Perl's kind of been expanding along with the universe" - Larry Wall

 

[133tcamel]

A word of caution for above.. I just made the code AS-IS without checking, so make a backup of your file before testing it.

---
cheers!
san

"The universe has been expanding, and Perl's kind of been expanding along with the universe" - Larry Wall

 

[djnsh]

Thanks 133tcamel for your reply - I have my program reading all the files in the directory and can produce an output file with the all the different extensions which exist with a common start as shown below:

e.g: apples234.564 -> use 234.564 part -> which produces bananas234.564

Apologies if my explanation of my problem has not been very specific however my real problem which I have been trying to solve is that I need two files combined into one like shown below without one writing over the other when each is opened. I have tried to summarise this paradox below:

apple456.334 => extract contents of file
} add contents of both files to produce a file called bananas456.334
orange456.334 => extract contents of file

Any help is greatly appreciated - I keep telling myself surely it can't be that difficult!