Editing Biopython (section)

=== Accessing online databases ===

Through the Bio.Entrez module, users of Biopython can download biological data from NCBI databases.  Each of the functions provided by the [[Entrez]] search engine is available through functions in this module, including searching for and downloading records.

<syntaxhighlight lang="pycon">
>>> # This script downloads genomes from the NCBI Nucleotide database and saves them in a FASTA file.
>>> from Bio import Entrez
>>> from Bio import SeqIO
>>> output_file = open("all_records.fasta", "w")
>>> Entrez.email = "my_email@example.com"
>>> records_to_download = ["FO834906.1", "FO203501.1"]
>>> for record_id in records_to_download:
...     handle = Entrez.efetch(db="nucleotide", id=record_id, rettype="gb")
...     seqRecord = SeqIO.read(handle, format="gb")
...     handle.close()
...     output_file.write(seqRecord.format("fasta"))
</syntaxhighlight>