Is faster to compare int values or strings?

Question

I have a series of values in a file and I'm iterating on them. Is it faster to run:

if FTB == "0":  
  do something  

or

if int(FTB) > 0:  
  do something  

Answer 1

Simply using the %timeit function in IPython:

FTB = 0

%timeit if FTB == 0: pass
10000000 loops, best of 3: 47 ns per loop

FTB = '0'

%timeit if int(FTB) == 0: pass
The slowest run took 9.47 times longer than the fastest. This could mean that an intermediate result is being cached.
1000000 loops, best of 3: 231 ns per loop

If you're planning to convert string -> integer on-the-fly using int(), then it looks like you're losing out on (relatively) quite a bit of speed. Comparisons involving FTB as a int to begin with are almost 80% faster than comparisons coercing a string FTB to integer.

Perhaps your original question was whether simply comparing already-typed objects (like something already an int or str and not needing type conversion) was different, speed-wise, in the case of strings and integers. In that case, for completeness:

FTB = '0'

%timeit if FTB == '0': pass
10000000 loops, best of 3: 49.9 ns per loop

FTB = 0

%timeit if str(FTB) == '0': pass
The slowest run took 8.62 times longer than the fastest. This could mean that an intermediate result is being cached.
1000000 loops, best of 3: 233 ns per loop

More sampling may be required, but naively it's tough to say there's a significant speed difference comparing str to str versus int to int. The biggest cost is the cost of calling either the int() or str() function to change types.

Answer 2

I am late for the party but here is a simple code that shows that there is almost no difference in python.

Also what may comes to my mind is that integers are limited by the lengt while a string can be any size (until you are out of memory) that's why I am increasing the size.

import time


theinteger = 2147483647
thestring = "2147483647"

stringtime = []
integertime = []

for i in range(0,99999):
    t0 = time.time()
    if thestring == "2147483647":
        print("hello")
    t1 = time.time();
    stringtime.append(t1 - t0)


    t0 = time.time()
    if theinteger == 2147483647:
        print("hello")
    t1 = time.time();
    integertime.append(t1 - t0)

    theinteger = theinteger + 1;
    thestring = str(theinteger)

print("time for string: " + str(sum(stringtime)/len(stringtime)))
print("time for integer: " + str(sum(integertime)/len(integertime)))

Answer 3

Integers are faster to compare because on the CPU it is just one operation. Strings are a representation of an array of characters. To compare a String you have to compare earch item in the array until you find a difference. So this are much more operations to compare the whole String. But the difference is in the range of a couple of nano seconds.