[Tutor] Logical Operators

[Alan Gauld]

> I am referring to http://www.ibiblio.org/obp/thinkCSpy/chap04.htm
> about Logical operators
>

You might find the functional programming topic in my tutorial 
interesting for a comparison. Look at the subsection 
"Short Circuit Evaluation" for some relevant examples.

> I did not understood
>>>  x = 5
>>>  x and 1
>1
>>>  y = 0
>>>  y and 1
>0
>
> How 5 and 1 means 1 and 0 and 1 means 0

In Python any non zero value is considered True.
So 5 and 1 are two true values and 

True and True = True

whereas 0 and 1 means:
 
False and True = False (ie zero)

Are you familiar with Trutrh tables and the concepts of Boolean Logic?
If not you may need some further explanation. If so a reasonable 
explanation appears on Wikipedia:

http://en.wikipedia.org/wiki/Truth_table

HTH,

Alan G
Author of the learn to program web tutor
http://www.freenetpages.co.uk/hp/alan.gauld