How do I read a random line from one file?

Question

Is there a built-in method to do it? If not how can I do this without costing too much overhead?

Answer 1

import random
lines = open('file.txt').read().splitlines()
myline =random.choice(lines)
print(myline)

For very long file: seek to random place in file based on it's length and find two newline characters after position (or newline and end of file). Do again 100 characters before or from beginning of file if original seek position was <100 if we ended up inside the last line.

However this is over complicated, as file is iterator.So make it list and take random.choice (if you need many, use random.sample):

import random
print(random.choice(list(open('file.txt'))))