Single Statement Exception Checking

Question

I'm just curious if this exists. After programming python for the better part of a year I've never come across it.

Is there a python function that is c-compiled (for faster access in comprehensions) that checks an exception:

A function like the following:

def no_exception(function, *args, **kwargs):
    try:
        function(*args, **kwargs)
    except Exception:
        return False
    return True

You could use it in this case

# values is full of data
new_values = [float(n) if no_exception(float, n) else n for n in values]

Exception handling is core to Python, why wouldn't that be fast? — Martijn Pieters, Mar 18 '13 at 15:41
List comprehensions slow down significantly if you have to make any non-C calls -- or at least that is how I understand it. — Garrett Berg, Mar 18 '13 at 16:55

score 1 · Accepted Answer · answered Mar 18 '13 at 15:47

1

No

at least not in the standard library. Otherwise the assertRaises method in the Python unittest module would use it. See: http://pythonhosted.org/gchecky/unittest-pysrc.html#TestCase.failUnlessRaises

You can of course write your own c implementation easily.

answered Mar 18 '13 at 15:47

Bernhard Kausler

Thanks for the response! For some reason I was pretty convinced that I had missed something, but looks like I didn't :) – Garrett Berg Mar 18 '13 at 16:52

1 Answers1