STD_3 - Adjacency Matrix.py

import sys

class Graph(object):
    
    def __init__(self, size):
        self.adjMatrix = []
        for i in range(size):
            self.adjMatrix.append([0 for i in range(size)])
        ###print(self.adjMatrix)
        self.size = size
#v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v

    '''Adjacency Matrix
    input: edges
    output: unweighted matrix of values
    Implements a method to add, remove, and display edges of an adjacency matrix
    '''

        
    def edge(self, vertex1, vertex2, task):            #takes the values passed in the section of code below
        if task == "add":
            print("adding edge ",vertex1+1,vertex2+1)   #shows the user what is happening
            self.adjMatrix[vertex1][vertex2] = 1        #sets the value of the matrix to 1 at the location entered
            self.adjMatrix[vertex2][vertex1] = 1        #undirected, so there will be symmetry in the matrix
        elif task == "del":
            print("removing edge",vertex1+1,vertex2+1)
            self.adjMatrix[vertex1][vertex2] = 0
            self.adjMatrix[vertex2][vertex1] = 0
            
    
    
    def dispMatrix(self):                           #this section lays out the matrix and spaces everything so its more readable
        rowCount = 1                                #the edges are entered starting from 0, but we want the matrix to be displayed from 1 onwards
        xStart = 1                                  #also want the columns to be 1 or higher
        xLim = self.size                            #will change the number of columns based on how many values exist
        xLine = self.size * 3                       #multiplied by 3 as a hyphen is roughly a third of the length of a letter
        
        print()
        print(end='    ')                           #keeps the printing on the same line
        
        for i in range(0,xLim):                     #will increase the number of columns until the maximum is reached
            print("",xStart, end=' ')
            xStart += 1
            
        print()
        print("   ","-"*xLine)                      #prints dividing line for readability
        
        for row in self.adjMatrix:                  #will print each row in the matrix
            print(rowCount, "|", row)
            rowCount += 1
        print(end='')
            
#^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^     

#remember list indexing - this is 1 out, unless we start the matrix at 0 (not a +ve integer)     
def main():
        g = Graph(6)
        
#v v v v v v v v v v v v v v v v v v v v v v
        g.edge(0,0,"add")
        g.edge(0,2,"add")
        g.edge(1,2,"add")
        g.edge(2,5,"add")
        g.edge(4,4,"add")
        g.edge(3,5,"add")     #these simply populate the matrix with values, starting from 0

        g.edge(2,0,"del")         #this removes one of the values from the matrix

        g.dispMatrix()      #calls the function to display the matrix
#^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
        
if __name__ == '__main__':
   main()