[Tutor] try, except syntax

[Shall, Sydney]

MAC OS X 10.13.6

Anaconda python 3.6.5

Anaconda IPython 6.4.0

I am having difficulty in using the try, except form.

I copy and paste a minimal program to illustrate my problem.


#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Thu Aug  2 15:41:15 2018

@author: sydney
"""
uvc = 2
msg = "Bad argument provided, the value of uvc must be a float."

try:
     type(uvc) == float
except TypeError as e:
     print(e, msg)

try:
     0.0 > uvc < 1.0
except ValueError:
     print("Bad argument provided. The value of uvc must be "
       "greater than 0.0 and less than 1.0.")




if type(uvc) != float:
     raise TypeError("Bad argument provided. And this is also old test."
                     " The value of UVC must be a float. This is old test")
if uvc < 0.0 or uvc > 1.0:
     raise ValueError("Bad argument provided. The value of uvc must be "
                      "greater than 0.0 and less than 1.0. This is old 
test")


My problem is this.

The two, 'if statements' at the end of the little program work as 
intended. And I have been using them in a larger program for some time 
and they have been checked regularly and they work as intended.

I am now rewriting a class, as recommended by both Alan and Steven, in 
which I have previously used these formulations.

This time, I thought that perhaps it would be more "pythonic" to write 
them as try, except. But I cannot find the correct format. I have read 
and reread the books and the documentation, but I am clearly stupid 
today. Either I do not need this change or I have written the try, 
except incorrectly. I am sure that I am making an elementary mistake.

Will someone please show tell me whether I should use try, except 
instead of if ... and then what is the correct syntax.

Thanks as always.

-- 

_________

Professor Sydney Shall
Department of Haematology/Oncology
Phone: +(0)2078489200
E-Mail: sydney.shall
[Correspondents outside the College should add @kcl.ac.uk]