All,
Windows 10, python 3.6.
I am trying to create a data structure. I might be using the wrong term here,
but I am calling it a hierarchical tree. The properties of the tree I am trying
to create is:
* A single root node
* A node can only have a single parent.
* A parent can have multiple children.
* Each node is unique.
This is also my first attempt in doing Object coding ever. Thus the terminology
I am not going to use correct. 😊
Data structure:
records = [‘the brown fox',
‘the brown cow’,
‘the brown car’,
‘the yellow car’,
‘the green house’,
‘yellow flowers’,
‘the quick brown fox’]
What I am trying to do:
I want to create a tree structure that stores the first word under the root,
the 2nd word under the first word as a child, ETC. the word ‘the’ for example
can only occur once as a node. Below is an example of the tree structure I am
trying to achieve:
Root
Root / the
Root / the / brown
Root / the / brown / fox
Root / the / brown / cow
Root / the / brown / car
Root / the / yellow
Root / the / yellow / car
Root / the / green
Root / the / green / house
Root / the / quick
Root / the / quick / brown
Root / the / quick / brown / fox
Root / yellow
Root / yellow / flowers
The code I have used to break up the words and build a dictionary to identify
the unique words plus the hit count:
nar_dict = {}
for text in records:
words = text.split()
l = len(words)
for i in range(1, l+1):
# only method I have found to correctly join the words.
tmp_list = words[:i]
key = ' '.join(tmp_list)
nar_dict[key] = 0
# perform the searches using dictionary key and count the number of hits.
for key, item in nar_dict.items():
print (key, item)
for line in records:
if line.startswith(key):
nar_dict[key] += 1
The result is (note, the output below is using a different data set):
{'the': 5, 'the brown': 3, 'the brown cow': 2, 'the brown car': 1, 'the
yellow': 1, 'the yellow car': 1, 'yellow': 2, 'yellow house': 1, 'the quick':
1, 'the quick fox': 1, 'yellow flowers': 1}
The code below works fine if I want to have a single parent and a single child.
The init definition I have used an empty array to store the children. I am not
sure how I can reference the new node back to the parent node. I have looked at
some packages like anytree and I got completely lost with the code. I have
looked for examples on the net and did not find anything I could understand.
Here is my code thus far with the children as a list.
# Value = hit counter
# Name = node name
class Node:
def __init__(self, name, value):
self.parent = None
self.child = []
self.name = name
self.value = value
def add_child(self, name, value):
# Compare the new value with the parent node
if self.name:
if name != self.name:
if self.child is None:
self.parent = self.child
self.child = Node(name, value)
else:
self.child.add_child(name, value)
else:
self.name = name
self.value = value
# Print the tree
def PrintTree(self):
if self.child:
self.child.PrintTree()
print( self.name, self.value),
I want to be able to do the following syntax:
Node.children[-1]value
Child = Node.children[0].children[0]
Parent = child.parent.name
I know I will have to write a search and walk functionality.
Any comments and tips on how to fix the parent issue. I would be grateful.
Hopefully this is not to open ended. Done my best to be very specific. 😊
Sean – Open ended question master 😊
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