if is faster than try?

py_except_speed.py

#!/usr/bin/env python3
from os.path import dirname, realpath
import sys
from timeit import Timer

sys.path.append(dirname(realpath(__file__)))

def ifway3(b):
    a=1
    if not b == 0:
    	ret = a/b

def ifway3_0():
    ifway3(0)

def ifway3_1():
    ifway3(1)

def tryway3(b):
    a=1
    try:
        ret=a/b
    except:
        pass

def tryway3_0():
    tryway3(0)

def tryway3_1():
    tryway3(1);

def dorun(callable):
    number, total_elapsed = Timer(callable).autorange()
    return total_elapsed/number

if __name__ == '__main__':
    for warmup in [True, False]:
        for method in [('ifway3_0', ifway3_0, ), ('tryway3_0', tryway3_0, ), ('ifway3_1', ifway3_1, ), ('tryway3_1', tryway3_1, ), ]:
            # Docs from Timer suggest that shortest time is most
            # likely to be closest to the limit. Variance (longer
            # times) is likely due to OS stealing timeslices and other
            # factors. So grab three samples per thing.
            elapsed = min(dorun(method[1]) for x in range(0, 3))
            if not warmup:
                print(','.join(str(x) for x in [method[0], elapsed]))

run.txt

$ python py_except_speed.py
ifway3_0,2.295694221095319e-07
tryway3_0,4.635965666751378e-07
ifway3_1,2.6982194153560267e-07
tryway3_1,2.3311285575462116e-07
$ uname -a
MSYS_NT-10.0 DESKTOP-A4G2C0J 2.6.0(0.304/5/3) 2016-09-07 20:45 x86_64 Msys
$ python -VV
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)]