File Reading

[toxicxarrow]

This assignment is technically complete according to my instructions, but I would like to polish it up a bit for my own learning experience. Basically, I was tasked to display 15 numbers in a file, then calculate the average of said numbers.

# Initialize constants
total = 0
lines = 0
file = 0
average = 0

# Gather all numbers in file for display
with open('numbers.dat', 'r') as file:
    lines = file.read()

# Add all numbers in file
for add in open('numbers.dat'):
    total += int(add.strip())

# Calculate the average of numbers in file
average = total / 15
average = round(average, 2)

#Print all numbers in file
print('The numbers in the file are:')
print(lines)

# Print the average of numbers in file
print('The average of those numbers is:')
print(average)

# Close file
file.close()

# END #

Question 1:
In this line of code:

# Calculate the average of numbers in file
average = total / 15
average = round(average, 2)

How can I replace the "15" with the number of integers that are actually in the file? Say I wanted to put 20 numbers in there instead of 15 to calculate the average, I'd like the total to be divided by the amount of numbers there are, not just a constant.

Question 2: What can I add to ignore spaces in the file, and only use the numbers on each line? The code works fine if the numbers are in a nice column without any spaces; however, I get an error if there is a single space in between the numbers.

Please keep any suggestions as close to the initial code as possible, and thank you for reading this far.

Cheers.