Perl | split() Function

split() is a string function in Perl which is used to split or you can say to cut a string into smaller sections or pieces. There are different criteria to split a string, like on a single character, a regular expression(pattern), a group of characters or on undefined value etc.. The best thing about this function that user can specify how many sections to split the string into.

Syntax:

split /Pattern/, Expression, Limit

or

split /Pattern/, Expression

or

split /Pattern/

or

Split

In the above syntax, Pattern is specified a regular expression which provides the criteria to split the string. The Expression is the string which is to be split. The Limit is kind of restriction which stops the splitting at (n-1)th pattern found in the string.

Return Value: This method returns the value in two context as follows:

In Array Context: Here it returns a list of the fields which found in Expression. If no Expression is specified then it returns $_.

In Scalar Context: Here it returns the number of fields which found in Expression and then stored the fields in the @_ array.

There are different ways to use split() Function as follows:

• Splitting on a Character
• Splitting among a String without Limit
• Splitting among a String with Limit
• Splitting on a Undefined value
• Splitting on a Regex(Pattern)
• Splitting on Hash
• Splitting on Space

Splitting on a Character

User can break or split the string on different characters like comma(,) backslash(\) etc. This type of splitting is generally used when you have to parse the data from another program or a file. Don’t use split() to parse the CSV(comma separated value) files. If there are commas in your data then use Text::CSV instead.

Example:

# Perl program to demonstrate the splitting on character

#!/usr/bin/perl
use strict;
use warnings;

# Here character is comma(, )
my $str = 'Geeks, for, Geeks';

# using split() function
my @spl = split(', ', $str);

# displaying result using foreach loop
foreach my $i (@spl)
{
    print "$i";
}

Output:

GeeksforGeeks

Splitting among String without any Limit

This also works same as the splitting on the character. Here string’s data is separated by two !!.

Example:

# Perl program to demonstrate the
# splitting among string without Limit

#!/usr/bin/perl
use strict;
use warnings;

# string which is separated by !! sign
my $str = 'GFG!!Geeks!!55!!GeeksforGeeks';

# using split function without Limit
my @spl = split('!!', $str);

# displaying string after splitting
foreach my $i (@spl)
{
    print "$i\n";
}

Output:

GFG
Geeks
55
GeeksforGeeks

Splitting among String with Limit

This also works same as the splitting on the character. Here string’s data is separated by two !!. Here the user can restrict the number of sections the string will split into by passing the third argument in split function which will be a positive integer value. In below example user pass the Limit as 3 so it will restrict the splitting of the string into 3, even there are the 4 occurrences of !! in the string.

Example:

# Perl program to demonstrate the
# splitting on string with Limit

#!/usr/bin/perl
use strict;
use warnings;

# string which is separated by !! sign
my $str = 'GFG!!Geeks!!55!!GeeksforGeeks';

# using split function with Limit
my @spl = split('!!', $str, 3);

# displaying string after splitting
foreach my $i (@spl)
{
    print "$i\n";
}

Output:

GFG
Geeks
55!!GeeksforGeeks

Splitting on an undefined value

If the user will try to split on an undefined value, then the string will split on every character.

Example:

# Perl program to demonstrate the
# splitting on undefined value

#!/usr/bin/perl
use strict;
use warnings;

# string to be split
my $str = 'GeeksforGeeks GFG';

# using split function
my @spl = split(undef, $str);

# displaying string after splitting
foreach my $i (@spl)
{
    print "$i\n";
}

Output:

G
e
e
k
s
f
o
r
G
e
e
k
s
 
G
F
G

Runtime Error:

Use of uninitialized value in regexp compilation at /home/38ececda726bcb7e68fb7b41eee5b8d9.pl line 12.

Splitting on a Pattern or Regex

Sometimes user may want to split the string on a pattern(regex) or a particular type of character. Here we will use the special character classes to make pattern of digits(integer) as follows:

Example:

# Perl program to demonstrate the
# splitting on a pattern(regex)

#!/usr/bin/perl
use strict;
use warnings;

# string to be split
my $str = 'Geeks1for2Geeks';

# using split function
# \d+ will match one or more
# integer numbers & placed
# between two //
my @spl = split(/\d+/, $str);

# displaying string after splitting
foreach my $i (@spl)
{
    print "$i\n";
}

Output:

Geeks
for
Geeks

Splitting into a hash

A user can split the data or string into the hash instead of an array. Basically, a hash is a key/value pair. Before splitting user must have knowledge about the hashes.

Example:

# Perl program to demonstrate the
# splitting into the hash

#!/usr/bin/perl
use strict;
use warnings;

# hash to be split
my $has = 'GFG=1;GEEKS=2;PROGEEK=3';

# using split function
my %spl = split(/[=;]/, $has);

# after splitting displaying the values
foreach my $i (keys %spl)
{
    print "$i:$spl{$i}\n";
}

Output:

GFG:1
GEEKS:2
PROGEEK:3

Splitting on Space

Here space doesn’t mean only ‘ ‘ this space but it also includes the newline, tabs etc.

Example:

# Perl program to demonstrate the
# splitting on space

#!/usr/bin/perl
use strict;
use warnings;

# string to be splitted
my $str = "ProGeek\n\nSudo\nPlacements";

# using split function
my @spl = split(' ', $str);

# Displaying result by printing
# 'GFG' either side of the
# value, so that user can see
# where it split
foreach my $i (@spl)
{
    print "GFG${i}GFG\n";
}

Output:

GFGProGeekGFG
GFGSudoGFG
GFGPlacementsGFG

Important Points To Remember

• As split() function also returns the value in scalar context. So for storing the return values user have to define some scalar values according to the number of sections of splitting. In below example there will be 4 values after splitting so here user will define the 4 scalars values and store the return values.

  Example:

  # Perl program to demonstrate the
  # splitting on string and storing
  # values in scalars
  
  #!/usr/bin/perl
  use strict;
  use warnings;
  
  # string which is separated by !! sign
  my $str = 'GFG!Sudo!GeeksforGeeks!ProGeek';
  
  # using split function and
  # storing values in scalars
  my ($sc1, $sc2, $sc3, $sc4) = split('!', $str);
  
  # displaying string after splitting
  print "$sc1\n$sc2\n$sc3\n$sc4";
  Output:

  GFG
  Sudo
  GeeksforGeeks
  ProGeek
  

• There may be a situation when user don’t pass in a string to split, then by default split() function will use the $_ and if user don’t pass a Expression i.e. the string to split on then it will use ‘ ‘(a space).

  Example:

  # Perl program to demonstrate the
  # split() function and context
  
  #!/usr/bin/perl
  use strict;
  use warnings;
  
  # using foreach loop containing string values
  foreach ('G F G', 'Geeks for Geeks')
  {
      # using split() function
      my @spl = split;
  
      # displaying values to be split
      print "Split $_:\n";
  
      foreach my $i (@spl)
      {
          print " $i\n";
      }
  }
  Output:

  Split G F G:
   G
   F
   G
  Split Geeks for Geeks:
   Geeks
   for
   Geeks
  

• If the delimiter is present at the starting of the string which is to be split, then the first element of return values will be empty and that will store into the array. In below example we have this situation and we are printing the empty value of resulted array:

  Example:

  # Perl program to demonstrate the
  # split() function with the Delimiter
  # at the start of the string
  
  #!/usr/bin/perl
  use strict;
  use warnings;
  
  # string containing delimiter(, )
  # at the starting
  my $str = ', GFG, Geeks';
  
  # using split function
  my @spl = split(', ', $str);
  
  # printing "Array_Element: " with each
  # returned value so that you can see
  # the empty one
  foreach my $i (@spl)
  {
      print "Array_Element: $i\n";
  }
  Output:

  Array_Element: 
  Array_Element: GFG
  Array_Element: Geeks
  

• If you want to keep the delimiter in result also then simply put that delimiter inside the parentheses.

  Example:

  # Perl program to demonstrate the
  # split() function and keeping
  # the delimiter
  
  #!/usr/bin/perl
  use strict;
  use warnings;
  
  # string to be split
  my $str = 'Geeks1for2Geeks';
  
  # using split function
  # \d+ will match one or more
  # integer numbers & placed
  # between two // and () to
  # keep the delimiter in result
  my @spl = split(/(\d+)/, $str);
  
  # displaying string after splitting
  foreach my $i (@spl)
  {
      print "$i\n";
  }
  Output:

  Geeks
  1
  for
  2
  Geeks