Prim's algorithm on existing graph

I plotted a graph using text input file now I have to apply prim's algorithm to it. How can I do it ? Below is my code for generating a graph using a text file

import matplotlib.pyplot as plt
import networkx as nx

f= open('input10.txt')
G=nx.Graph()
x=f.read()
x=x.split()
y=[float(i) for i in x]

for i in range(1,30,3):
        G.add_node(y[i],pos=(y[i+1],y[i+2]))

def last_index(y):
    return len(y)-1
z=last_index(y)

for i in range(31,z-3,5):
    G.add_edge(y[i],y[i+1],weight=(y[i+2]))

pos=nx.get_node_attributes(G,'pos')
weight=nx.get_edge_attributes(G,'weight')
plt.figure()
nx.draw(G,pos)

Use the nodes u=y[i], v=y[i+1] and weight=y[i+2], and create adjacency matrix or adjacency list of the graph and then apply prim's algorithm, you can find a good and easy tutorial here :Prim’s Minimum Spanning Tree