Converting Between Data FormatsΒΆ

Any data in a schema that can be read by DendroPy, can be saved to files in any schema that can be written by DendroPy. Converting data between formats is simply a matter of calling readers and writers of the appropriate type.

Converting from FASTA schema to NEXUS:

>>> import dendropy
>>> cytb = dendropy.DnaCharacterMatrix.get(path="pythonidae_cytb.fasta", schema="fasta")
>>> cytb.write(path="pythonidae_cytb.nexus", schema="nexus")

Converting a collection of trees from NEXUS schema to Newick:

>>> import dendropy
>>> post_trees = dendropy.TreeList()
>>> post_trees.read(
...         file=open("pythonidae.nex.run1.t", "r")
...         schema="nexus",
...         tree_offset=200)
>>> post_trees.read(
...         path="pythonidae.nex.run2.t",
...         schema="nexus",
...         tree_offset=200)
>>> post_trees.write(
...     path="pythonidae.mcmc.newick",
...     schema="newick")

Converting a single tree from Newick schema to NEXUS:

>>> import dendropy
>>> mle = dendropy.Tree.get(path="pythonidae.mle.newick", schema="newick")
>>> mle.write(path="pythonidae.mle.nex", schema="nexus")

Collecting data from multiple sources and writing to a NEXUS-formatted file:

>>> import dendropy
>>> ds = dendropy.DataSet()
>>> tns = ds.new_taxon_namespace()
>>> ds.attach_taxon_namespace(tns)
>>> ds.read(
...     path="pythonidae_cytb.fasta",
...     schema="fasta",
...     data_type="dna")
>>> ds.read(
...     path="pythonidae_aa.nex",
...     schema="nexus")
>>> ds.read(
...     path="pythonidae_morph.nex",
...     schema="nexus")
>>> ds.read(
...     path="pythonidae_trees.tre",
...     schema="newick")
>>> ds.write(
...     path="pythonidae_combined.nex",
...     schema="nexus")

Note how we create a new TaxonNamespace instance using the new_taxon_namespace method, and then “bind” or attach it to the DataSet instance using the attach_taxon_namespace method. This ensures that all new data parsed by the DataSet instance will reference the same TaxonNamespace instance, i.e., all taxon labels will be mapped to the same set of Taxon objects. Alternatively, we could also have explicitly passed in the TaxonNamespace instance to use for each reading operation:

>>> import dendropy
>>> ds = dendropy.DataSet()
>>> tns = ds.new_taxon_namespace()
>>> ds.read(
...     path="pythonidae_cytb.fasta",
...     schema="fasta",
...     data_type="dna",
...     taxon_namespace=tns)
>>> ds.read(
...     path="pythonidae_aa.nex",
...     schema="nexus",
...     taxon_namespace=tns)
>>> ds.read(
...     path="pythonidae_morph.nex",
...     schema="nexus",
...     taxon_namespace=tns)
>>> ds.read(
...     path="pythonidae_trees.tre",
...     schema="newick",
...     taxon_namespace=tns)
>>> ds.write(
...     path="pythonidae_combined.nex",
...     schema="nexus",
...     taxon_namespace=tns)