Question

Write a PYTHON program that allows the user to navigate the lines of text in a file. The program should prompt the user for a filename and input the lines of text into a list. The program then enters a loop in which it prints the number of lines in the file and prompts the user for a line number. Actual line numbers range from 1 to the number of lines in the file. If the input is 0, the program quits. Otherwise, the program prints the line associated with that number.

Hint:

To loop for line numbers from the user until she enter 0 and prints the line’s number followed by the line, use the following code:

while True:

            print("The file has", len(lines), "lines.")

            if len(lines) == 0:

                        break

            lineNumber = int(input("Enter a line number [0 to quit]: "))

            if lineNumber == 0:

                        break

            elif lineNumber > len(lines):

                        print("ERROR: line number must be less than or equal to", len(lines))

            else:

                        print(lineNumber, ": ", lines[lineNumber-1])

Answer 1

filename = input('Enter file name: ')
lines = []
with open(filename, 'r') as f:
    for line in f:
        lines.append(line.strip())

while True:
    print("The file has", len(lines), "lines.")
    if len(lines) == 0:
        break
    lineNumber = int(input("Enter a line number [0 to quit]: "))
    if lineNumber == 0:
        break
    elif lineNumber > len(lines):
        print("ERROR: line number must be less than or equal to", len(lines))
    else:
        print(lineNumber, ": ", lines[lineNumber - 1])