Python's two-dimension dictionary definition and implementation method, twodimensioncode

Python's two-dimension dictionary definition and implementation method, twodimensioncode

This article describes how to define and implement the "two-dimension dictionary" dictionary in Python. We will share this with you for your reference. The details are as follows:

Dict in Python allows quick search. Is there a two-dimensional dictionary like an array with two-dimensional arrays? For example, when I need to search for two keywords. 2D dict

dict_2d = {'a': {'a': 1, 'b': 3}, 'b': {'a': 6}}

And

dict_2d['a']['b']

. However, adding a new "key-value" pair is complicated. For one-dimensional dictionaries, you can use

dict_1d = dict()dict_1d['a'] = 1

Or

dict_1d.update({'a': 1})

. However, when "2-D" dictionary adds a new "key-value" pair

dict_2d['a']['c'] = 8

. Because the two-layer keys and values of the two-dimensional dictionary are confused, you need to determine whether the first key already exists. You can use a function to add a two-dimensional dictionary:

def addtwodimdict(thedict, key_a, key_b, val):  if key_a in adic:    thedict[key_a].update({key_b: val})  else:    thedict.update({key_a:{key_b: val}})

For example, it can be used to find the distance between cities.

mapdict = dict()addtwodimdict(mapdict, 'Beijing', 'Guangzhou', 1897)addtwodimdict(mapdict, 'Chengdu', 'Guangzhou', 1243)addtwodimdict(mapdict, 'Guangzhou', 'Shanghai', 1212)addtwodimdict(mapdict, 'Beijing', 'Chengdu', 1516)addtwodimdict(mapdict, 'Chengdu', 'Shanghai', 1657)addtwodimdict(mapdict, 'Beijing', 'Shanghai', 1075)print 'The distance between Chengdu and Guangzhou is '，mapdict['Chengdu']['Guangzhou']

It is quite convenient.