How to read and delete first n lines from file in Python - Elegant Solution [duplicate]

Answer 1

A file is it's own iterator.

n = 3
nfirstlines = []

with open("bigFile.txt") as f, open("bigfiletmp.txt", "w") as out:
    for x in xrange(n):
        nfirstlines.append(next(f))
    for line in f:
        out.write(line)

# NB : it seems that `os.rename()` complains on some systems
# if the destination file already exists.
os.remove("bigfile.txt")
os.rename("bigfiletmp.txt", "bigfile.txt")