Why python For in Loop is so slow? -

i tested performance for in loop in python. contains loop , plus operations. takes 0.5secs. how can more faster?

import time  start_time = time.time()  val = -1000000 in range(2000000):     val += 1  elapsed_time = time.time() - start_time  print(elapsed_time) # 0.46402716636657715 

the way faster using itertools module written in c gain c performance:

example:

from itertools import repeat   def foo():     val = -1000000     in range(2000000):         val += 1     return val   def bar():     val = -1000000     return val + sum(repeat(1, 2000000)) 

results:

$ python -m timeit -s "from foo import foo" "foo()" 10 loops, best of 3: 102 msec per loop  prologic@daisy wed jun 03 19:51:54  ~/tmp $ python -m timeit -s "from foo import bar" "bar()" 100 loops, best of 3: 10.5 msec per loop 

but have t8 wonder why summing val += 1 in loop 2,000,000 times?

the optimal solution (of course) is:

val = 100000