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Any way to detect division by zero?

asked 2010-12-08 12:02:45 -0500

Shu gravatar image

updated 2010-12-09 08:04:33 -0500

niles gravatar image

In Sage, is there any way (function call) to check whether a given expression will produce division by zero error. Is something like the following possible?

if IsDivisionByZero(expr): return False

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answered 2010-12-08 12:17:53 -0500

You can use Python try...except blocks to catch a ZeroDivisionError. For example, I define the two functions

def foo(x):
    return 1/x

def bar(x):
    try:
        return 1/x
    except ZeroDivisionError:
        # error handling: do whatever you want here
        print "Returning positive infinity..."
        return Infinity

This is what the output looks like when giving various inputs into these two functions.

sage: foo(1)
1
sage: foo(0)
Traceback (click to the left of this block for traceback)
...
ZeroDivisionError: Rational division by zero
sage: bar(1)
1
sage: bar(0)
Returning positive infinity...
+Infinity

You can use try...except blocks outside of function definitions as well.

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2

answered 2010-12-08 12:14:32 -0500

Something like this:

def temp(x):
    try:
        return 3/x
    except ZeroDivisionError:
        return False

Then

sage: temp(2)
3/2
sage: temp(0)
False
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Asked: 2010-12-08 12:02:45 -0500

Seen: 232 times

Last updated: Dec 09 '10