with statements and exceptions

[John Salerno]

John Salerno wrote:
> I'm thinking about using a with statement for opening a file, instead of 
> the usual try/except block, but I don't understand where you handle an 
> exception if the file doesn't open. For example:
> 
> with open('myfile', 'r'):
>     BLOCK
> 
> I assume that BLOCK can/will contain all the other stuff you want to do, 
> which may involve try/except blocks, but what if the initial open() call 
> fails (for lack of file, etc.)? Is this the purpose of the with 
> statement, to handle this itself? Is there still some way that I can 
> respond to this and show the user an error message?
> 
> Thanks.

Let me just toss this in as well:

     def create_sql_script(self):
         with open('labtables.sql') as sql_script:
             return sql_script.read()

Does the file still get closed even though I have a return statement 
inside the with block?

Thanks.