Autovivification.py

# -*- coding: utf-8 -*-
#
# colletor: willowj
#
# One-line Tree in Python
# ref https://gist.github.com/hrldcpr/2012250
# https://en.wikipedia.org/wiki/Autovivification#Python

from __future__ import unicode_literals
from __future__ import print_function

from collections import defaultdict

#----method 1 ##->----------------------------------------
# https://gist.github.com/hrldcpr/2012250


class mydefaultdict(defaultdict):

    def __getattr__(self, attr):
        return self[attr]

    def __setattr__(self, attr, val):
        self[attr] = val


def tree(): return mydefaultdict(tree)

#----method 2 ##->----------------------------------------
# https://en.wikipedia.org/wiki/Autovivification#Python


class Tree(dict):
    """docstring for Tree"""

    def __missing__(self, key):
        value = self[key] = type(self)()
        return value

    __getattr__ = dict.__getitem__

    __setattr__ = dict.__setitem__
#----##->----------------------------------------

taxonomy = Tree()  # or tree()


taxonomy.Animalia.Chordata.Mammalia.Carnivora.Felidae.Felis.cat
taxonomy.Animalia.Chordata.Mammalia.Carnivora.Felidae['Panthera']['lion']
taxonomy.Animalia.Chordata.Mammalia.Carnivora['Canidae']['Canis']['dog']
taxonomy.Animalia.Chordata.Mammalia.Carnivora['Canidae']['Canis']['coyote']
taxonomy['Plantae']['Solanales']['Solanaceae']['Solanum']['tomato']
taxonomy['Plantae']['Solanales']['Solanaceae']['Solanum']['potato']
taxonomy['Plantae']['Solanales']['Convolvulaceae']['Ipomoea']['sweet potato']


def add(t, path):
    for node in path:
        t = t[node]

add(taxonomy,
    'Animalia>Chordata>Mammalia>Cetacea>Balaenopteridae>Balaenoptera>blue whale'.split('>'))

#----##->----------------------------------------


def ptratree(t, depth=0):
    """ print a tree """
    for k in t.keys():
        print("%s %2d %s" % (" "*4*depth, depth, k))
        depth += 1
        ptratree(t[k], depth)
        depth -= 1

ptratree(taxonomy)
import pprint
pprint.pprint(taxonomy)

#----#->----------------------------------------
'''###for method 1
def dicts(t): return {k: dicts(t[k]) for k in t}

print(dicts(taxonomy))
'''

######################################################################
# attr to Url
######################################################################


class Url(str):
    """attr to Url"""
    def __new__(cls, base, sept="/"):
        return cls.__base__.__new__(cls, base)

    def __init__(self, base, sept="/"):
        self.sept = sept

    def __add__(self, other):
        x = super(Url, self).__add__(self.sept + str(other))
        return Url(x, self.sept)

    __getattr__ = __add__

github = Url('https://github.com', sept="**")
print(github.willowj.py_tricks.master + 5 + 9)
# https://github.com**willowj**py_tricks**master**5**9


class Url(str):
    __add__ = lambda self, name: Url(str.__add__(self, "/" + str(name)))
    __getattr__ = __add__

url_path = Url('https://github.com').willowj.py_tricks.master + 5 + 8 + 9

print(url_path)
# https://github.com/willowj/py_tricks/master/5/8/9