Read a number of random lines from a file in Python

Question

Could someone show me how I could read a random number of lines from a file in Python?

Answer 1

Your requirement is a bit vague, so here's another slightly different method (for inspiration if nothing else):

from random import random
lines = [line for line in open("/some/file") if random() >= .5]

Compared with the other solutions, the number of lines varies less (distribution around half the total number of lines) but each line is chosen with 50% probability, and only one pass through the file is required.