Reading a CSV file with graphviz - python-3.x

Question

The current project I have to do involves reading data from a CSV file and using graphviz to show a visual representation of the data. this is what the code looks like:
import graphviz
import pandas
import os
import math
def save_graph_as_jpg(graph, filename):
graph.save('temp.dot')
src = graphviz.Source.from_file('temp.dot')
src.render(filename, format="jpg")
os.remove(filename)
os.remove('temp.dot')
class Node:
def __init__(self, data, left = None, right = None):
self.left = left
self.right = right
self.data = data
df = pandas.read_csv('decisiontree.csv', index_col = "ID") # df is "data frame"
print(df.to_string())
print(df.info)
nodes = []
nodeMap = {None:None}
for index, row in df[::-1].iterrows():
row = df.index(int[index])
if isinstance(df.loc[row][3], float) and math.isnan(df.loc[row][3]):
df.loc[row][3] = None
if isinstance(df.loc[row][2], float) and math.isnan(df.loc[row][2]):
df.loc[row][2] = None
nodeMap[df.loc[row][0]] = Node(df.loc[row][1],nodeMap[df.loc[row][3]], nodeMap[df.loc[row][2]]), nodes.insert(0,df.loc[row][0])
graph = graphviz.Digraph('structs', filename='structs.gv', node_attr={'shape': 'plaintext', 'ordering':'out'})
for nodeID in nodes:
node = nodeMap[nodeID]
if node.left:
graph.edge(node.data, node.left.data)
if node.right:
graph.edge(node.data, node.right.data)
save_graph_as_jpg(graph, "Decisiontree")
When I run it using IDLE, it returns most of the code just fine, but it gets hung up on line 27:
row = df.index(int[index])
I get a traceback message saying the following:
Traceback (most recent call last):
File "C:\Users...... line 27, in <module>
row = df.index[index]
File "C:\Users......Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\pandas\core\indexes\base.py", line 5382, in __getitem__
result = getitem(key)
IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices
I changed it to:
row = df.index(int[index])
and now I get this as a traceback and index error:
Traceback (most recent call last):
File "C:\Users.......CTML AI\Week 3\Lab3.py", line 27, in <module>
row = df.index(int[index])
TypeError: 'type' object is not subscriptable

Answer 1

You are receiving that error because you tried to use square brackets with the int type, which would try to subscript int as if it were an array. That doesn't work because int is a type that can't be subscripted.[1][2] You probably want to use parentheses instead to cast the type of the index variable to integer. Try changing line 27 to
df.index(int(index))
However, it would work if you had an array named int, but naming your variables the same as builtin types or functions is probably not a good idea.
As of Python 3.9, some types can be subscripted in type hints, e.g. list[int].