How to print an array that it looks like a hash [duplicate] - perl

Question

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I need help in perl, how to write a code to get the output of my csv file in the form of a hash [closed]
(1 answer)
Closed 10 years ago.
I am new to Perl, and have to write a code which takes contents of a file into and array and print the output that it looks like a hash. Here is an example entry:
my %amino_acids = (F => ["Phenylalanine", "Phe", ["TTT", "TTC"]])
Out put should be exactly in above format.
Lines of Files are like this...
"Methionine":"Met":"M":"AUG":"ATG"
"Phenylalanine":"Phe":"F":"UUU, UUC":"TTT, TTC"
"Proline":"Pro":"P":"CCU, CCC, CCA, CCG":"CCT, CCC, CCA, CCG"
I have to take last codons after semicolon and ignore the first group.

Answer 1

Is it your intention to build the equivalent hash? Or do you really want the string format? This program uses Text::CSV to build the hash from the file and then dumps it using Data::Dump so that you have the string format as well.
use strict;
use warnings;
use Text::CSV;
use Data::Dump 'dump';
my $csv = Text::CSV->new({ sep_char => ':' });
open my $fh, '<', 'amino.txt' or die $!;
my %amino_acids;
while (my $data= $csv->getline($fh)) {
$amino_acids{$data->[2]} = [
$data->[0],
$data->[1],
[ $data->[4] =~ /[A-Z]+/g ]
];
}
print '$amino_acids = ', dump \%amino_acids;
output
$amino_acids = {
F => ["Phenylalanine", "Phe", ["TTT", "TTC"]],
M => ["Methionine", "Met", ["ATG"]],
P => ["Proline", "Pro", ["CCT", "CCC", "CCA", "CCG"]],
}
Update
If you really don't want to install modules (it is a very straightforward process and makes the code much more concise and reliable) then this does what you need.
use strict;
use warnings;
open my $fh, '<', 'amino.txt' or die $!;
print "my %amino_acids = (\n";
while (<$fh>) {
chomp;
my #data = /[^:"]+/g;
my #codons = $data[4] =~ /[A-Z]+/g;
printf qq{ %s => ["%s", "%s", [%s]],\n},
#data[2,0,1],
join ', ', map qq{"$_"}, #codons;
}
print ")\n";
output
my %amino_acids = (
M => ["Methionine", "Met", ["ATG"]],
F => ["Phenylalanine", "Phe", ["TTT", "TTC"]],
P => ["Proline", "Pro", ["CCT", "CCC", "CCA", "CCG"]],
)

Answer 2

Assuming you actually want valid perl as the output, this will do it:
open(my $IN, "<input.txt") or die $!;
while(<$IN>){
chomp;
my #tmp = split(':',$_);
if(#tmp != 5){
# error on this line
next;
}
my $group = join('","',split(/,\s*/,$tmp[4]));
print "\$amino_acids{$tmp[2]} = [$tmp[0],$tmp[1],[$group]];\n";
}
close $IN;
Using your sample lines, the output is:
$amino_acids{"M"} = ["Methionine","Met",["ATG"]];
$amino_acids{"F"} = ["Phenylalanine","Phe",["TTT","TTC"]];
$amino_acids{"P"} = ["Proline","Pro",["CCT","CCC","CCA","CCG"]];

Answer 3

#Borodin Thank you very much for your answer, actually I don't have to use Text::csv or Data::dump.I have to open a file and build the equivalent hash from the file.I am trying to do without using both, hopefully it will help.Thanks again!!!

Answer 4

Perl has no special method to print hashes. What you should probably do is create a hash when reading the file:
while (<FILE>) {
my #line = split ':'; # split the line into an array
$amino_acids{$line[0]} = \#line[1..-1]; # take elements 1..end
}
And then print out the hash one entry at a time:
foreach (keys %amino_acids) {
print "$_ => [", (join ",", #$amino_acids{$_}), "]\n";
}
Note that I didn't compile this, so it may need a small amount of work to get it done.