Hi Perlmonks,

I have three text files (1.txt, 2.txt & 3.txt) on desktop. Each file has 5 strings separated by comma. I am interested to upload these files without using <STDIN> and then to join the corresponding strings of the files based on length (two longest & two shortest). I have written a script (test.pl) which can find out the two longest and two shortest strings of each file. But I am at my wit's end to join the corresponding short and long strings across files based on length. I am looking forward to suggestions from you to sort out this problem. The text files, the script, the results of command script and the desired strings are given below:

Here goes the three text files:

1.txt is given below:

A
,AA
,AAA
,AAAA
,AAAAA
,
[download]

2.txt

T
,TT
,TTT
,TTTT
,TTTTT
,
[download]

3.txt

G
,GG
,GGG
,GGGG
,GGGGG
,
[download]

Here goes the script: test.pl

 
#!/usr/bin/perl  
use warnings;  
 
 @apple=(1 ... 3); 
     $nm=0; 
foreach my $num (@apple) {$nm++; 
  $output_fle="$nm.txt";
 
  if (-e $output_fle) { 
  open FILE,"$output_fle" or die "Couldn't open file: $!"; 
    $fle=join(" ",<FILE>);
    close FILE;  
  $fle=~ s/\s//g;  
  @fle=split(' ',$fle);     
  push  @all_file,@fle; 

  } # End of if LOOP for required files:  

}  # Last curly brace of Foreach LOOP for uploading all files: 

#########################
# Code for each file:  ##
#########################

    $file_no=0;
foreach my $each_fle ( @all_file) { $file_no++;
 
  @a=split(',',$each_fle);  
  $seq_no=0; 

foreach my $seq (@a) { $seq_no++; # For each sequence of the file
    $seq=~ s/,//g;  
    $seq= uc$seq;   
    $seq_len=length($seq); # For testing  

print"\n Element $seq_no of File $file_no: $seq
   Length: $seq_len\n";     

# push length & each seq to an array:     
     push  @names,$seq;  
     push  @values,$seq_len;  
    
    } # End of foreach LOOP for each file: 

#######################################################
# Find two lowest & two highest values of each file with sequences: 
#######################################################
use 5.010; 
use Data::Dumper; 
use constant IWANT => 2; 
my @data; 
my $pos=1; 
  
 for my $val (@values) { 
   my $name=shift @names; 
   my $rec=sprintf"\n Length %0.1f; Seq: %s",$val,$name; 
   push @data,$rec;} 

print"\n\nLength (Small to big) with sequences for File $file_no:\n";
 @data= sort @data; 
 for(0 .. IWANT-1) {say $data[$_];} 

print"\n";  
 print"\nLength (Big to small) with sequences for File $file_no:\n"; 
 for (1 .. IWANT) {say $data[-$_];}        

############################
# End Max & Min codes here: 
#############################

 @values=(); # To empty the array
 @names=();  # To empty the array
print"\n######## File $file_no ends ##############\n\n"; 

} # End of foreach LOOP for all files
 
exit; 
########################################
[download]

The results of the cmd goes like:

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\x>cd desktop

C:\Users\x\Desktop>test.pl

 Element 1 of File 1: A
   Length: 1

 Element 2 of File 1: AA
   Length: 2

 Element 3 of File 1: AAA
   Length: 3

 Element 4 of File 1: AAAA
   Length: 4

 Element 5 of File 1: AAAAA
   Length: 5


Length (Small to big) with sequences for File 1:

 Length 1.0; Seq: A

 Length 2.0; Seq: AA


Length (Big to small) with sequences for File 1:

 Length 5.0; Seq: AAAAA

 Length 4.0; Seq: AAAA

######## File 1 ends ##############


 Element 1 of File 2: T
   Length: 1

 Element 2 of File 2: TT
   Length: 2

 Element 3 of File 2: TTT
   Length: 3

 Element 4 of File 2: TTTT
   Length: 4

 Element 5 of File 2: TTTTT
   Length: 5


Length (Small to big) with sequences for File 2:

 Length 1.0; Seq: T

 Length 2.0; Seq: TT


Length (Big to small) with sequences for File 2:

 Length 5.0; Seq: TTTTT

 Length 4.0; Seq: TTTT

######## File 2 ends ##############


 Element 1 of File 3: G
   Length: 1

 Element 2 of File 3: GG
   Length: 2

 Element 3 of File 3: GGG
   Length: 3

 Element 4 of File 3: GGGG
   Length: 4

 Element 5 of File 3: GGGGG
   Length: 5


Length (Small to big) with sequences for File 3:

 Length 1.0; Seq: G

 Length 2.0; Seq: GG


Length (Big to small) with sequences for File 3:

 Length 5.0; Seq: GGGGG

 Length 4.0; Seq: GGGG

######## File 3 ends ##############
[download]

In addition to the above results, I need the following desired strings based on length:

Two shortest strings (small to big): 
 Seq 1: ATG
 seq 2: AATTGG 

Two longest strings (big to small):
 seq 1: AAAAATTTTTGGGGG 
 seq 2: AAAATTTTGGGG
[download]