Python if vs try-except

Question

I was wondering why the try-except is slower than the if in the program below.

def tryway():
    try:
        while True:
            alist.pop()
    except         


        

Answer 1

Just thought to toss this into the mix: I tried the following script below which seems to suggest that handling an exception is slower than handling an else statement:

import time

n = 10000000
l = range(0, n)
t0 = time.time()
for i in l:
    try:
        i[0]
    except:
        pass
t1 = time.time()
for i in l:
    if type(i) == list():
        print(i)
    else:
        pass
t2 = time.time()
print(t1-t0)
print(t2-t1)

gives:

5.5908801555633545
3.512694835662842

So, (even though I know someone will likely comment upon the use of time rather than timeit), there appears to be a ~60% slow down using try/except in loops. So, perhaps better to go with if/else when going through a for loop of several billion items.