A certainl part of an if() structure never gets executed.

Fábio Santos fabiosantosart at gmail.com
Fri Jun 14 05:05:02 EDT 2013


On 14 Jun 2013 09:56, "Nick the Gr33k" <support at superhost.gr> wrote:
>
> On 14/6/2013 11:03 πμ, Nick the Gr33k wrote:
>>
>> On 14/6/2013 4:14 πμ, Steven D'Aprano wrote:
>>>
>>> On Thu, 13 Jun 2013 17:26:18 +0300, Νικόλαος Κούρας wrote:
>>>
>>>> i just want 4 cases to examine so correct execute to be run:
>>>>
>>>> i'm reading and reading and reading this all over:
>>>>
>>>> if '-' not in ( name and month and year ):
>>>>
>>>> and i cant comprehend it.
>>>
>>>
>>> Don't just read it. Open the interactive interpreter and test it.
>>>
>>> name = "abcd"
>>> month = "efgh"
>>> year = "ijkl"
>>>
>>> print(name and month and year)
>>>
>>> If you run that, you will see what the result of
>>> (name and month and year) is. Now, ask yourself:
>>>
>>> "k" in (name and month and year)
>>>
>>> True or false? Check your answer:
>>>
>>> print("k" in (name and month and year))
>>
>>
>>
>>  >>> name="abcd"
>>  >>> month="efgh"
>>  >>> year="ijkl"
>>
>>  >>> print(name or month or year)
>> abcd
>>
>> Can understand that, it takes the first string out of the 3 strings that
>> has a truthy value.
>>
>>  >>> print("k" in (name and month and year))
>> True
>>
>> No clue. since the expression in parenthesis returns 'abcd' how can 'k'
>> contained within 'abcd' ?
>>
>>  >>> print(name and month and year)
>> ijkl
>>
>> Seems here is returning the last string out of 3 strings, but have no
>> clue why Python doing this.
>>
>>  >>> print("k" in (name and month and year))
>> True
>>  >>>
>>
>> yes, since expression returns 'ijkl', then the in operator can detect
>> the 'k' character within the returned string.
>>
>
> Someone want to explain this?

At the very least read the replies to your questions.
http://code.activestate.com/lists/python-list/644572/
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