Tab delineated file

Tab delineated files put tables of information into lines where each field is separated by a tab. The first line can be a header file giving titles or names to the columns.

Contents 1 Advantages over CSVs 2 Perl 2.1 Splitting the fields of the line into an array 2.2 A subfunction to return a hash reference out of a line 2.3 A subfunction to make a tab delineated line from a hash reference given a list of columns

[edit] 1 Advantages over CSVs

CSV files are also very common--but sometimes commas need to be a part of the fields, and it's harder to find an appropriate replacement. Tabs, however, can generally be replaced with a set of spaces in fields containing them with no ill effects.

[edit] 2 Perl

[edit] 2.1 Splitting the fields of the line into an array

my @line_fields = split( /\t/, $line );

[edit] 2.2 A subfunction to return a hash reference out of a line

# Input 1
#    Line to split into fields
# Input 2
#    A list of headers in an array
# Returns
#    A hash reference where each value of the line is accessible
#    by its column name, determined by the order of the list of
#    headers.
sub get_fields {
     my $line = shift( @_ );
     chomp( $line );
     my @line_fields = @_;

     my @fields = split( /\t/, $line );
     my %fields;

     foreach my $field_name (@line_fields) {
         $fields{$field_name} = shift( @fields );
     }

     return \%fields;
}

[edit] 2.3 A subfunction to make a tab delineated line from a hash reference given a list of columns

# Input 1
#    A hash reference where the key is the name of the
#    column field and the value is that column's value
#    for this line
# Input 2
#    An array of column header names.  This will be the
#    order for the columns used to make the lines.  If not
#    present, will sort the keys of the hash and use that
#    instead.
# Returns
#    A line of tab delineated values in the order of the
#    column header names given.
sub make_line {
     my $hash = shift( @_ );
     my @fields = @_;
     my @line;

     # if there are no specific fields, use the keys of the hash, sorted
     if( scalar( @fields ) == 0 ) {
         @fields = sort(keys(%$hash));
     }

     foreach my $field ( @fields ) {
         push( @line, $hash->{$field} );
     }

     return join( "\t", @line ) . "\n";
}