STD_3.py

class Graph(object):

    def __init__(self, size):
        self.adjMatrix = []                                                 #creating an empty list
        for i in range(size):                                               #for loop for the lngth of the input
            self.adjMatrix.append([0 for i in range(size)])                 #adding to the list
        self.size = size                                                    #assigning the variable size

    #methods for (1) adding a vertex; (2) adding an edge; (3) removing an edge; and (4) printing the
    #matrix should appear here
    
    def addVertex(self, vertNum):
        for i in self.adjMatrix:                                            #for loop of the list
            length_ = len(i)                                                #assigning the length from each loop

        newRow = vertNum - length_                                          #variable created from input minus the length

        for x in range(len(self.adjMatrix)):                                #for loop of the legnth of the list
            for i in range(newRow):                                         #nested for loop of the range of input
                self.adjMatrix[x].append(0)                                 #appending the list

        for i in self.adjMatrix:                                            #for loop of the list
            length_two = len(i)                                             #assinging the second legnth

        for y in range(newRow):                                             #for loop of the input
            self.adjMatrix.append(0 for i in range(length_two))             #assigning the vertex to the matrix

    def addEdge(self, v1, v2):                                              #code to add an edge
        if v1 == v2:                                                        #the two values are equal
            print(("Same vertex %d and %d" % (v1, v2)))                     #print out the equals vertexs
        self.adjMatrix[v1-1][v2-1] = 1                                      #assigning the first value to be 1
        self.adjMatrix[v2-1][v1-1] = 1                                      #assigning the second vaue to be 1
    
    def removeEdge(self, v1, v2):                                           #code to remove an edge
        if self.adjMatrix[v1-1][v2-1] == 0:                                 #if the edge doesn't equal 1
            print(("trueNo edge between %d and %d" % (v1, v2)))             #print that there is no edge between the two values
            return
        self.adjMatrix[v1-1][v2-1] = 0                                      #assigning the first value to be 0
        self.adjMatrix[v2-1][v1-1] = 0                                      #assigning the first value to be 0

    
    def containsEdge(self, v1, v2):                                         #assigning the first value to be 0
        return True if self.adjMatrix[v1-1][v2-1] > 0 else False            #returning true if the values are greater than 0
    def __len__(self):
        return self.size                                                    #returning the size

    def toString(self):                                                     #converts the matrix to a string
        for row in self.adjMatrix:                                          #for loop of each row
            for val in row:                                                 #for loop of each value
                print(('{:4}'.format(val)), end=' ')                        #printing the values in the rows
 
#remember list indexing - this is 1 out, unless we start the matrix at 0 (not a positive integer)     
def main():                                                                 #funciton containing the inputs
    g = Graph(6)
    g.addEdge(1, 2)
    #prints 1s in top row 3rd and 3rd row 1st
    g.addEdge(3,2)

    g.addEdge(3,1)
    g.addEdge(4,3)
    
    g.addVertex(6)
    g.toString()



if __name__ == '__main__':
   main()