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

You're setting alist only once. The first call to "tryway" clears it, then every successive call does nothing.

def tryway():
    alist = range(1000)
    try:
        while True:
            alist.pop()
    except IndexError:
        pass

def ifway():
    alist = range(1000)
    while True:
        if alist == []:
            break
        else:
            alist.pop()
if __name__=='__main__':
    from timeit import Timer
    print "Testing Try"
    tr = Timer("tryway()","from __main__ import tryway")
    print tr.timeit(10000)
    print "Testing If"
    ir = Timer("ifway()","from __main__ import ifway")
    print ir.timeit(10000)

>>> Testing Try
>>> 2.09539294243
>>> Testing If
>>> 2.84440898895