Python Try-Except: Why does it not catch it?

Question

I am trying to get the hang of try/ except and I just can't seem to get it working. I want it to stop for a negative or a very larger number:

try:
    h > 0.
except:
    return "Your distance (", h, ") is negative"
try:
    h < 3700000.
except:
    return "Your distance (", h, ") is outside the range this model"
else:
    # Return Correct Value:
    return g0*(r/(r+h))**2

Yet it keeps on going to the end no matter what value I throw at it... I've tried different things after except like false and other stuff, but none of them work:

>>> print(earth_gravity(1))
1.0
9.80649692152011
>>> print(earth_gravity(-1))
-1.0
9.806503078481338

score 3 · Accepted Answer · answered Apr 22 '15 at 23:06

3

Because no exception is raised. Use an if statement to check the trueness of the condition instead.

if h > 0:
   ...
elif ...:
   ...
else:
   ...

answered Apr 22 '15 at 23:06

Ignacio Vazquez-Abrams

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So try/except is strictly for errors coming from the language in that sense (and should not be used in this context)? – MaxQ Apr 22 '15 at 23:08
@MikeFoxtrot: From exceptional circumstances in the code. A simple comparison isn't exceptional. – Ignacio Vazquez-Abrams Apr 22 '15 at 23:10

Python Try-Except: Why does it not catch it?

1 Answers1