Simplest example of parsing text files of ITIS taxonomy

lookup.py

#!/usr/bin/python3

# globals
name={}
hierarchy={}
vernacular={}
synonyms={}

def loaddb():
    "Load up databases into dictionaries: name, hierarchy, vernacular"
    global name, hierarchy, vernacular, synonyms

    # Slurp up conversion from taxonomic serial number x to longname y
    f=open("longnames", "rb")
    for line in f:
        line=line.decode('latin-1')
        (x,y) = line.split('|')
        name[x]=y.rstrip()
    f.close()

    # Load in hierarchy, mapping taxonomic serial number n to hierarchy h
    f=open("hierarchy", "rb")
    for line in f:
        line=line.decode('latin-1')
        (h,n,*dummy) = line.split('|')
        hierarchy[n]=h.rstrip()
    f.close()

    # Read in the vernacular database (mapping 'European frog' to '173444')
    f=open("vernaculars", "rb")
    for line in f:
        line=line.decode('latin-1')
        (n,v,*dummy) = line.split('|')
        v=v.lower()
        if v not in vernacular:
            vernacular[v]=[]
        vernacular[v].append(n)
    f.close()

    # Read in the synonyms database (mapping obsolete TSN to current TSN)
    f=open("synonym_links", "rb")
    for line in f:
        line=line.decode('latin-1')
        (n,s,dummy) = line.split('|')
        synonyms[n]=s
    f.close()

def printhierarchy(v):
    # Look up by vernacular and print hierarchy
    try:
        vlist=vernacular[v.lower()] 
        # Print out the hierarchy 
        for n in vlist:
            if n in hierarchy:
                h=hierarchy[n] 
            elif n in synonyms:
                h=hierarchy[synonyms[n]]
            else:
                return False
            print( v + ':' )
            for level in h.split('-'):
                print ( ' → ' + name[level] )
    except KeyError:
        print( "‘"+v+"’ not found" )

# Main
loaddb()
from sys import argv
arg=' '.join( [ str(x) for x in argv[1:] ] )
printhierarchy(arg)