Re: split function

[Marshall]

in reply to split function

A more normal formulation of this would be:

while (<$fh_in>)
{
   chomp;  #deletes the trailing "new line" line ending
           #this works for files from any OS
   my @array = split(';',$_);
}

$a,$b,$1,$2 etc are special variables that Perl uses.
Never assign values to any of these.
These should be "read only" variables as far as your code is concerned.

while (<$fh_in>)
{
   print;   #prints $_ (the line from $fh_in)
   my ($first_thing) = split(';',$_);
   print "$first_thing\n";
}

Is there a limit of length that split function can handle, otherwise, it will truncate the line into next line. is there a way how to resolve it?

There is no "hard limit" on the length of the expression that split can handle nor is there a limit on the size of the resulting array. ...well ok.. there is a limit somewhere, but this limit is certainly not 36 ... it is in the range of many thousands or even more... In a practical sense: NO. There is no limit, meaning that the limit is so huge that you won't encounter it in normal programming.

[tcheungcm]

Thanks. Here is my code

sub split_the_element{
my ($local_fh) = @_;
while (readline $local_fh) {
  #my @records = split(/;/);
  my ($var1, $var2, $var3, $var4, $var5, $var6, $var7, $var8, $var9, $
+var10, $var11, $var12,
      $var13, $var14, $var15, $var16, $var17, $var18, $var19, $var20, 
+$var21, $var22, $var23, $var24,
      $var25, $var26, $var27, $var28, $var29, $var30, $var31, $var32, 
+$var33, $var34, $var35, $var36) =split(/;/);
  print "1 element $var1\n";
  print "2 element $var2\n";
  print "3 element $var3\n";
  print "4 element $var4\n";
  print "5 element $var5\n";
  print "6 element $var6\n";
  print "7 element $var7\n";
  print "8 element $var8\n";
  print "9 element $var9\n";
  print "10 element $var10\n";
  print "11 element $var11\n";
  print "12 element $var12\n";
  print "13 element $var13\n";
  print "14 element $var14\n";
  print "15 element $var15\n";
  print "16 element $var16\n";
  print "17 element $var17\n";
  #my $i=0;
  #foreach($i=1; $i<=36; $++) {
  # print "$i element $var$i\n"
  #}
 }
}

Here is my data file 1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;16;17;18;19;20;21;22;23;24;25;26;27;28;29;30;31;32;33;34;35;36

And the output:

1 element 1

2 element 2

3 element 3

4 element 4

5 element 5

6 element 6

7 element 7

8 element 8

9 element 9

10 element 10

11 element 11

12 element 12

13 element 13

14 element 14

15 element 15

16 element 16

17 element 17

1 element 21

2 element 22

3 element 23

4 element 24

5 element 25

6 element 26

7 element 27

8 element 28

9 element 29

10 element 30

11 element 31

12 element 32

13 element 33

14 element 34

15 element 35

16 element 36

It seems that data file can split up to 17th elements and then the rest will start to split on the next line.

[Marshall]

#!/usr/bin/perl -w
use strict;

my $data ='1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;16;17;18;19;20;21;22;23
+;24;25;26;27;28;29;30;31;32;33;34;35;36';

my @elements = split (';',$data);

my $number =1;
foreach my $element (@elements)
# or could be:
# foreach my $element (split (';',$data))
{
  print "number=$number\t element=$element\n";
  $number++;
}

The above works.

I think that there is a "new line" in your data file file.

sub split_the_element
{
   my ($fh_in) = @_; #or: my $fh_in = shift;
   my @result;
   while (<$fh_in>) 
   {
      chomp;
      foreach my $element (split ';', $_)
      {
          push (@result, $element); 
      }
   }
   return @result;
}

[Anonymous Monk]

It seems that data file can split up to 17th elements and then the rest will start to split on the next line.

Um, no, that would be jumping to conclusions.

my @junk = split /;/, join ';', 'a'..'z', 'A'..'J';
print int(@junk),"\n";
print "@junk\n";
print "$_=$junk[$_]  " for 0,1,10,20,33,34,-1;
__END__
36
a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I 
+J
0=a  1=b  10=k  20=u  33=H  34=I  -1=J

The reason your foreach loop doesn't work is explained in this FAQ, read all 3 parts

1. Why it's stupid to `use a variable as a variable name'
2. A More Direct Explanation of the Problem
3. What if I'm Really Careful?

Read this if you want to cut your development time in half!

Read perlintro and the array /loop chapters of http://learn.perl.org/books/beginning-perl/

[rovf]

It seems that data file can split up to 17th elements and then the rest will start to split on the next line.

I don't see from your output that split would behave in this way, but you can easily verify this, by doing a

print "LINE JUST READ IS: [$_]\n";

just before the split.

[NodeReaper]

This node was taken out by the NodeReaper on Jan 28, 2012 at 12:00 UTC
Reason: [choroba]: Read: duplicate of Re^4: split function

You may view the original node and the consideration vote tally.

[tcheungcm]

Thanks all. I think the problem is happened on the readline. After I add the line before the split

 print "Line just read is $_\n";

the output is

Line just read is 1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;16;17;18;19;20;

Line just read is 21;22;23;24;25;26;27;28;29;30;31;32;33;34;35;36

I also checked the lenght of each line is limited 51. Anyone would have clue?