Analyze and display user defined columns from a CSV file.

csvTool.pl

#!/usr/bin/env perl
#
#  Analyze CSV files in order to see only the columns you specify.
#  Display the headers of the CSV in order to get column names and/or numbers.
#  Use the column names/numbers in order to only display those columns to standard out.
#
use strict;
use Getopt::Std;

my %options=();
getopts("c:laf:s:", \%options);

init();

sub init{
  if($options{f}){
    if($options{l}){
      listhead();
    }
    elsif($options{a}){
      if($options{c}){
        analyze();
      } else { die "Did not include -c <column name>,<column name>\n\n"; }
    }
  }
  else { die "Did not include -f <filename>\n\n"; }
}

###############
#
# Display the header of the input file
#
# ./csvTool -l -f file.csv [-s '\|']
#
###############
sub listhead {
  my $filName;
  my $separator;

# Check to make sure the proper switch and a filename were provided
  if($options{f}){
    $filName = "$options{f}";
  }else { die "Did not include -f <filename>\n\n";}

  $separator = "$options{s}" || ",";

# Read first line to get header row
  open(FILE1,"<", "$filName") or die "Could not read from $filName!";
  my $header = <FILE1>;
  my @fileFields = split(/$separator/, uc($header));
  my $fileFieldsLen = @fileFields;

  my %index;
  @index{@fileFields} = (0..$#fileFields);
  for my $field (@fileFields){
        my $idx = $index{$field} + 1;
    print "$idx $field\n";
  }
}


###############
#
# Analyze input file
#
# ./csvTool -a -f file.csv -c 1,2,3 [-s '\t']
#
# ./csvTool -a -f file.csv -c id,email [-s ';']
#
###############
sub analyze {
  my $filName;
  my @inFields;
  my $separator;

# Check to make sure the proper switch and a filename were provided
  if($options{f}){
    $filName = "$options{f}";
  }else { die "Did not include -f <filename>\n\n"; }

  if($options{c}){
    @inFields = split(/,/,$options{c});
  }else { die "Did not include -c <column name>,<column name>\n\n"; }

  $separator = "$options{s}" || ",";
# Read first line to get header row
  open(FILE1,"<", "$filName") or die "Could not read from $filName!";
  my $header = <FILE1>;
  my @fileFields = split(/$separator/, uc($header));
  my $fileFieldsLen = @fileFields;

# Get column numbers of each user requested field
  my $useFields = undef;
  my %index;
  @index{@fileFields} = (0..$#fileFields);

  for my $inField (@inFields){
    $inField =~ s/^\s+|\s+$//g;
    $inField = uc($inField);
    if($inField =~ /[0-9]/){
      for(my $c = 0; $c < $fileFieldsLen; $c++){
       if($c eq $inField - 1){
         $useFields .= $inField - 1 .",";
         last;
       }
     }
    } else{
      $useFields .= "$index{$inField},";
    }
  }
  $useFields = join(",",split(/,/,$useFields));

# Read the rest of the file, displaying only those columns that the user requested
  my $cnt = 0;
  while (!eof(FILE1)) {
    my $line = <FILE1>;
    $line =~ tr/\"//d;
    chomp($line);
    my @row = split(/$separator/,$line);
    my $reportRows = undef;
    for my $c (split(/,/,$useFields)){
      $reportRows = $reportRows . "$row[$c]      ";
    }
    print "$reportRows\n";
    $cnt++;
  }
  close FILE1;
}