Bio::DB::Taxonomy list
SummaryIncluded librariesPackage variablesSynopsisDescriptionGeneral documentationMethods
Bio::DB::Taxonomy::list - An implementation of Bio::DB::Taxonomy
that accepts lists of words to build a database
Package variables
No package variables defined.
Included modules
  use Bio::DB::Taxonomy;
my $db = Bio::DB::Taxonomy->new( -source => 'list' ); my @ranks = ('superkingdom', 'class', 'genus', 'species'); my @names = ('Eukaryota', 'Mammalia', 'Homo', 'Homo sapiens'); $db->add_lineage(-names => \@names, -ranks => \@ranks); @names = ('Eukaryota', 'Mammalia', 'Mus', 'Mus musculus'); $db->add_lineage(-names => \@names, -ranks => \@ranks);
This is an implementation which uses supplied lists of words to create a
database from which you can extract Bio::Taxon objects.
Methods description
newcode    nextTop
 Title   : new
Usage : my $obj = Bio::DB::Taxonomy::list->new();
Function: Builds a new Bio::DB::Taxonomy::list object
Returns : an instance of Bio::DB::Taxonomy::list
Args : optional, as per the add_lineage() method.
 Title   : add_lineage
Usage : my @names = ('Eukaryota', 'Mammalia', 'Homo', 'Homo sapiens');
my @ranks = ('superkingdom', 'class', 'genus', 'species');
$db->add_lineage( -names => \@names, -ranks => \@ranks );
Function: Add a lineage to the database, where the lineage is described by
a list of scientific names in the order root->leaf. The rank of each
name can optionally be described by supplying an additional list
of rank names in the same order (eg. superkingdom->species).
Returns : 1 for success
Args : -names => [] : array ref of scientific names, REQUIRED
-ranks => [] : array ref of rank names, same order as above, OPTIONAL
 Title   : get_num_taxa
Usage : my $num = $db->get_num_taxa();
Function: Get the number of taxa stored in the database.
Returns : A number
Args : None
 Title   : get_taxon
Usage : my $taxon = $db->get_taxon(-taxonid => $taxonid)
Function: Get a Bio::Taxon object from the database.
Returns : Bio::Taxon object
Args : A single value which is the ID of the taxon to retrieve
OR named args, as follows:
-taxonid => Taxonomy ID (NB: these are not NCBI taxonomy ids but
'list' pre-fixed ids unique to the list database).
-name => String (to query by a taxonomy name). A given taxon name
can match different taxonomy objects. When that is the
case, a warning is displayed and the first matching taxon
is reported. See get_taxonids() to get all matching taxon
-names => Array ref of lineage names, like in add_lineage(). To
overcome the limitations of -name, you can use -names to
provide the full lineage of the taxon you want and get a
unique, unambiguous taxon object.
 Title   : get_taxonids
Usage : my @taxonids = $db->get_taxonids('Homo sapiens');
Function: Searches for a taxonid (generated by the list module) based on a
query string. Note that multiple taxonids can match to the same
supplied name.
Returns : array of integer ids in list context, one of these in scalar context
Args : string representing taxon's name
 Title   : ancestor
Usage : my $ancestor_taxon = $db->ancestor($taxon)
Function: Retrieve the full ancestor taxon of a supplied Taxon from the
Returns : Bio::Taxon
Args : Bio::Taxon (that was retrieved from this database)
 Title   : each_Descendent
Usage : my @taxa = $db->each_Descendent($taxon);
Function: Get all the descendents of the supplied Taxon (but not their
descendents, ie. not a recursive fetchall).
Returns : Array of Bio::Taxon objects
Args : Bio::Taxon (that was retrieved from this database)
Methods code
sub new {
    my ($class, @args) = @_;
    my $self = $class->SUPER::new(@args);
    my %args = @args;
    delete $args{'-source'};

    $self->add_lineage(%args) if %args;
    return $self;
sub add_lineage {
    my ($self, @args) = @_;
    my ($names, $ranks) = $self->_rearrange([qw (NAMES RANKS)], @args);
    $self->throw("-names must be supplied and its value must be an array reference")
        unless $names && ref($names) eq 'ARRAY';

    my $names_idx = scalar @$names - 1;

    if ($ranks) {
        $self->throw("-ranks must be an array reference")
            unless ref($ranks) eq 'ARRAY';
        $self->throw("The -names and -ranks lists must be of equal length")
            unless $names_idx == scalar @$ranks - 1;
    # This is non-trivial because names are not guaranteed unique in a taxonomy,
# and neither are name&rank combinations. Furthermore, different name&rank
# combinations can actually refer to the same taxon, eg. when one time
# 'Homo'&'genus' is supplied, while another time 'Homo'&'no rank'.
# name&rank&ancestor could well be unique (or good enough 99.9999% of the
# time), but we have the added complication that lineages could sometimes be
# supplied with differing numbers of taxa. Ideally we want to realise that
# the first of these two lineages shares all its nodes with the second:
# ('Mammalia', 'Homo', 'Homo sapiens')
# ('Mammalia', 'Hominidae', 'Homo', 'Homo sapiens')
# Clearly with limited information we can't do a perfect job, but we can try
# and do a reasonable one. So, let's just do the trivial implementation now
# and see how bad it is! (assumes ranks are unique except for 'no rank')
my $ancestors = $self->{ancestors}; my $node_data = $self->{node_data}; my $name_to_id = $self->{name_to_id}; my $children = $self->{children}; my $my_ancestor_id = ''; my @node_ids; for my $i (0 .. $names_idx) { my $name = $names->[$i]; my $rank = $ranks->[$i]; # if undef, this node has 'no rank'
# This is a new node with a new id if we haven't seen this name before.
# It's also always a new node if this is the first lineage going into
# the db.
# We need to handle, however, situations in the future where we try to
# merge in a new lineage but we have non-unique names in the lineage
# and possible missing classes in some lineages, e.g.
# '... Anophelinae, Anopheles, Anopheles, Angusticorn, Anopheles...'
# merged with
# '... Anophelinae, Anopheles, Angusticorn, Anopheles...'),
# but still need the 'tree' to be correct
# Look for a node that is consistent with this lineage
my $node_id; SAME_NAMED: for my $same_id (@{$name_to_id->{$name}}) { # Taxa are the same if it they have the same ancestor or none
my $this_ancestor_id = $ancestors->{$same_id} || ''; if ($my_ancestor_id eq $this_ancestor_id) { $node_id = $same_id; last SAME_NAMED; } # Compare children
next if $i >= $names_idx; # this taxon has no child
my $my_child_name = $names->[$i + 1]; #while ( my ($this_child_id, undef) = each %{$children->{$same_id}} ) {
for my $this_child_id (keys %{$children->{$same_id}}) { if ($my_child_name eq $node_data->{$this_child_id}->[0]) { # both children have same name
if ($my_ancestor_id) { my @s_ancestors; while ($this_ancestor_id = $ancestors->{$this_ancestor_id}) { if ($my_ancestor_id eq $this_ancestor_id) { $my_ancestor_id = $ancestors->{$same_id}; push @node_ids, @s_ancestors, $my_ancestor_id; $node_id = $same_id; last SAME_NAMED; } unshift @s_ancestors, $this_ancestor_id; } } else { # This new lineage (@$names) doesn't start at the
# same root as the existing lineages. Assuming
# '$name' corresponds to node $same_id");
$node_id = $same_id; last SAME_NAMED; } } } } if (not defined $node_id) { # This is a new node. Add it to the database, using the prefix 'list'
# for its ID to distinguish it from the IDs from other taxonomies.
my $next_num = ++$self->{node_ids}; $node_id = $prefix.$next_num; push @{$self->{name_to_id}->{$name}}, $node_id; $self->{node_data}->{$node_id} = [$name]; } if ( (defined $rank) && (not defined $node_data->{$node_id}->[1]) ) { # Save rank if node in database has no rank but the current node has one
$node_data->{$node_id}->[1] = $rank; } if ($my_ancestor_id) { if ($self->{ancestors}->{$node_id} && $self->{ancestors}->{$node_id} ne $my_ancestor_id) { $self->throw("The lineage '".join(', ', @$names)."' and a ". "previously stored lineage share a node name but have ". "different ancestries for that node. Can't cope!"); } $self->{ancestors}->{$node_id} = $my_ancestor_id; } $my_ancestor_id = $node_id; push @node_ids, $node_id; } # Go through the lineage in reverse so we can remember the children
for (my $i = $names_idx - 1; $i >= 0; $i--) { $self->{children}->{$node_ids[$i]}->{$node_ids[$i+1]} = undef; } return 1;
sub get_num_taxa {
    my ($self) = @_;
    return $self->{node_ids} || 0;
sub get_taxon {
    my ($self, @args) = @_;

    my $taxonid;
    if (scalar @args == 1) {
        # Argument is a taxon ID
$taxonid = $args[0]; } else { # Got named arguments
my ($name, $names); ($taxonid, $name, $names) = $self->_rearrange([qw(TAXONID NAME NAMES)], @args); if ($name) { $names = [$name]; } if ($names) { $name = $names->[-1]; my @taxonids = $self->get_taxonids($name); $taxonid = $taxonids[0]; # Use provided lineage to find correct ID amongst several matching IDs
if ( (scalar @taxonids > 1) && (scalar @$names > 1) ) { for my $query_taxonid (@taxonids) { my $matched = 1; my $db_ancestor = $self->get_taxon($query_taxonid); for (my $i = $#$names-1; $i >= 0; $i--) { my $query_ancestor_name = $names->[$i]; $db_ancestor = $db_ancestor->ancestor; my $db_ancestor_name = ''; if ($db_ancestor) { $db_ancestor_name = $db_ancestor->node_name; } if (not ($query_ancestor_name eq $db_ancestor_name) ) { $matched = 0; last; # done testing this taxonid
} } if ($matched == 1) { @taxonids = [$query_taxonid]; $taxonid = $query_taxonid; last; # done testing all taxonids
} } } # Warn if several taxon IDs matched
if (scalar @taxonids > 1) { $self->warn("There were multiple ids (@taxonids) matching '$name',". " using '$taxonid'") if scalar @taxonids > 1; } } } # Now that we have the taxon ID, retrieve the corresponding Taxon object
my $taxon; my $node = $self->{node_data}->{$taxonid}; if ($node) { my ($sci_name, $rank) = @$node; $taxon = Bio::Taxon->new( -name => $sci_name, -object_id => $taxonid, # not an ncbi taxid, simply an object id
); if ($rank) { $taxon->rank($rank); } # we can't use -dbh or the db_handle() method ourselves or we'll go
# infinite on the merge attempt
$taxon->{'db_handle'} = $self; $self->_handle_internal_id($taxon, 1); } return $taxon; } *get_Taxonomy_Node =\& get_taxon;
sub get_taxonids {
    my ($self, $name) = @_;
    return @{$self->{name_to_id}->{$name} || []};

*get_taxonid =\& get_taxonids;
sub ancestor {
    my ($self, $taxon) = @_;
    $taxon || return; # for bug 2092, or something similar to it at least: shouldn't need this!
$self->throw("Must supply a Bio::Taxon") unless ref($taxon) && $taxon->isa('Bio::Taxon'); $self->throw("The supplied Taxon must belong to this database") unless $taxon->db_handle && $taxon->db_handle eq $self; my $id = $taxon->id || $self->throw("The supplied Taxon is missing its id!"); my $ancestor_id = $self->{ancestors}->{$id} || return; return $self->get_taxon($ancestor_id);
sub each_Descendent {
    my ($self, $taxon) = @_;
    $self->throw("Must supply a Bio::Taxon") unless ref($taxon) && $taxon->isa('Bio::Taxon');
    $self->throw("The supplied Taxon must belong to this database")
        unless $taxon->db_handle && $taxon->db_handle eq $self;
    my $id = $taxon->id || $self->throw("The supplied Taxon is missing its id!");
    my @children;
    while ( my ($child_id, undef) = each %{$self->{children}->{$id}} ) {
        push @children, ($self->get_taxon($child_id) || next);
    return @children;

General documentation
It is possible this module could do something like store the data it builds
up to disc. Would that be useful?
At any rate, this is why the module is called 'list' and not 'in_memory' or
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the Bioperl mailing list. Your participation is much appreciated.                  - General discussion - About the mailing lists
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address it. Please include a thorough description of the problem
with code and data examples if at all possible.
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Report bugs to the Bioperl bug tracking system to help us keep track
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AUTHOR - Sendu BalaTop
The rest of the documentation details each of the object methods.
Internal methods are usually preceded with a _
Bio::DB::Taxonomy Interface implementationTop