Python large file read optimization

for.py

n = 0
f = open("my_huge_file.txt", "r")
for line in f:
  n+=1
f.close()
print(n)

# 2m19.330s

for_mutable.py

n = [0]
f = open("my_huge_file.txt", "r")
for line in f:
  n[0]+=1
f.close()
print(n)

# 1m36.63s

perl.pl

$n = 0;
open(FILE, "<my_huge_file.txt");
$n++ while (<FILE>);
close(FILE);
print $n;

# 1m36.755s

readline.py

n = 0
f = open("my_huge_file.txt", "r")
line = f.readline()
while line:
  n+=1
  line = f.readline()
f.close()
print(n)

# 4m4.982s