LEARN Python: UP to EXPERT CODING. Are you EXPERT enough in Python programming to ignore THIS? by Dominique SAGE

Author:Dominique SAGE [SAGE, Dominique]
Language: eng
Format: azw3, epub
Published: 2020-05-19T16:00:00+00:00

Dealing With Errors

In order to better handle program errors and exceptions, it’s best to change what Python displays by default. Keep in mind that at the end of the day it’s the user’s experience that matters, not the programmer’s vision. Achieving perfection is close to impossible, but you can give your program the ability to make your user understand what’s going on when something unexpected happens. That is why in programming we have the so-called “try/except” blocks. The syntax is simple:

try:

Add what your program is supposed to do, except for the following

Exception:

Now, instruct the app on what to do if something mentioned above isn’t possible for whatever reason.

Let’s grab our earlier example and instruct the application to deal with a file that can’t be found:

try:

myFile = open ('employees.csv')

print(myFile.name)

except Exception:

print ("Oops, I can’t find any file named employees.csv in here")

What we do is attempt to open the file, as stated in the “try” section. If the file is opened, then the command within the try statement will be executed and the file will be opened and displayed. However, if the program raises an exception, then it won’t just close with a default error. It will display a message that clearly explains what happens so that any user without programming knowledge can understand.

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