[Tutor] List comprehensions

[Bob Gailer]

At 07:05 PM 1/12/2005, Kent Johnson wrote:
>I suppose if it's an expression, it must be valid, eh? Otherwise it's 
>something else.

At 06:41 PM 1/12/2005, Max Noel wrote:

>On Jan 13, 2005, at 01:13, Bob Gailer wrote:
>
>>At 04:48 PM 1/12/2005, Kent Johnson wrote:
>>>If you mean for j to be a list of foobar(item) then use
>>>j=[foobar(item) for item in x]
>>>
>>>The first part of the list comp can be any valid expression.
>>
>>Does that mean that there are invalid expressions? I'd enjoy seeing an 
>>example.
>
>Here's an obvious one:
>
>j = [foobar(item)/0 for item in x]

I like Kent's response.

foobar(item)/0 is a "valid" expression. It fits the grammar of expressions. 
The fact that it raises an exception does not make it an invalid expression.

Consider foobar(item)/xyz. It is valid. If xyz == 0 then it will also raise 
an exception.

Bob Gailer
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