AttributeError Problem

[animemaiden]

Hi,

I'm trying to display a graph in Tkinter  that reads a graph from a file and 
displays it on a panel which the first line in the file contains a number that 
indicates the number of vertices (n). The vertices are labeled as 0,1,…,n-1. 
Each subsequent line, with the format u x y v1, v2, …describes that the vertex 
u is located at position (x,y) with the edges (u,1). (u,v2), and so on.


I'm using Python 3.2.3 and I keep getting this error:

numberOfVertices = int(infile.readline().decode()) # Read the first line from 
the file
AttributeError: 'str' object has no attribute 'readline'


Here is my code:

from tkinter import * # Import tkinter
from tkinter import filedialog



def displayGraph(canvas, vertices, edges):
radius = 3
for vertex, x, y in vertices:
canvas.create_text(x - 2 * radius, y - 2 * radius, text = str(vertex), 
tags = "graph")
canvas.create_oval(x - radius, y - radius, x + radius, y + radius, fill 
= "black", tags = "graph")

for v1, v2 in edges:
canvas.create_line(vertices[v1][1], vertices[v1][2], vertices[v2][1], 
vertices[v2][2], tags = "graph")

def main():

infile = filedialog.askopenfilename()


numberOfVertices = int(infile.readline().decode()) # Read the first line 
from the file
print(numberOfVertices)

vertices = []
edges = []
for i in range(numberOfVertices):
items = infile.readline().strip().split() # Read the info for one vertex
vertices.append([int(items[0]), int(items[1]), int(items[2])])
for j in range(3, len(items)):
edges.append([int(items[0]), int(items[j])])

print(vertices)
print(edges)

infile.close()  # Close the input file

window = Tk() # Create a window
window.title("Display a Graph") # Set title

frame1 = Frame(window) # Hold four labels for displaying cards
frame1.pack()
canvas = Canvas(frame1, width = 300, height = 200)
canvas.pack()

displayGraph(canvas, vertices, edges)

window.mainloop() # Create an event loop

main()

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Re: AttributeError Problem

[animemaiden]

On Tuesday, April 23, 2013 7:41:27 PM UTC-4, animemaiden wrote:
> Hi,
> 
> 
> 
> I'm trying to display a graph in Tkinter  that reads a graph from a file and 
> displays it on a panel which the first line in the file contains a number 
> that indicates the number of vertices (n). The vertices are labeled as 
> 0,1,…,n-1. Each subsequent line, with the format u x y v1, v2, …describes 
> that the vertex u is located at position (x,y) with the edges (u,1). (u,v2), 
> and so on.
> 
> 
> 
> 
> 
> I'm using Python 3.2.3 and I keep getting this error:
> 
> 
> 
> numberOfVertices = int(infile.readline().decode()) # Read the first line from 
> the file
> 
> AttributeError: 'str' object has no attribute 'readline'
> 
> 
> 
> 
> 
> Here is my code:
> 
> 
> 
> from tkinter import * # Import tkinter
> 
> from tkinter import filedialog
> 
> 
> 
> 
> 
> 
> 
> def displayGraph(canvas, vertices, edges):
> 
> radius = 3
> 
> for vertex, x, y in vertices:
> 
> canvas.create_text(x - 2 * radius, y - 2 * radius, text = 
> str(vertex), tags = "graph")
> 
> canvas.create_oval(x - radius, y - radius, x + radius, y + radius, 
> fill = "black", tags = "graph")
> 
> 
> 
> for v1, v2 in edges:
> 
> canvas.create_line(vertices[v1][1], vertices[v1][2], vertices[v2][1], 
> vertices[v2][2], tags = "graph")
> 
> 
> 
> def main():
> 
> 
> 
> infile = filedialog.askopenfilename()
> 
> 
> 
> 
> 
> numberOfVertices = int(infile.readline().decode()) # Read the first line 
> from the file
> 
> print(numberOfVertices)
> 
> 
> 
> vertices = []
> 
> edges = []
> 
> for i in range(numberOfVertices):
> 
> items = infile.readline().strip().split() # Read the info for one 
> vertex
> 
> vertices.append([int(items[0]), int(items[1]), int(items[2])])
> 
> for j in range(3, len(items)):
> 
> edges.append([int(items[0]), int(items[j])])
> 
> 
> 
> print(vertices)
> 
> print(edges)
> 
> 
> 
> infile.close()  # Close the input file
> 
> 
> 
> window = Tk() # Create a window
> 
> window.title("Display a Graph") # Set title
> 
> 
> 
> frame1 = Frame(window) # Hold four labels for displaying cards
> 
> frame1.pack()
> 
> canvas = Canvas(frame1, width = 300, height = 200)
> 
> canvas.pack()
> 
> 
> 
> displayGraph(canvas, vertices, edges)
> 
> 
> 
> window.mainloop() # Create an event loop
> 
> 
> 
> main()

Also, it reads data from a file.
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Re: AttributeError Problem

[animemaiden]

On Tuesday, April 23, 2013 8:02:08 PM UTC-4, Skip Montanaro wrote:
> > numberOfVertices = int(infile.readline().decode()) # Read the first line 
> > from the file
> 
> > AttributeError: 'str' object has no attribute 'readline'
> 
> ...
> 
> > infile = filedialog.askopenfilename()
> 
> 
> 
> This is just returning a filename.  You need to open it to get a file
> 
> object.  For example:
> 
> 
> 
> infile = filedialog.askopenfilename()
> 
> fd = open(infile)
> 
> ...
> 
> numberOfVertices = int(fd.readline().decode())
> 
> 
> 
> Skip
Thanks, but now I have this error AttributeError: 'str' object has no attribute 
'decode'
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