[Tutor] Print record x in a file

[David Holland]

 --- "Jacob S." <keridee at jayco.net> wrote: 
> > This will get a random record
> > I hope you do not think the comments are
> patronising
> > but you did say you are new so I did not want to
> give
> > naked code.
> >
> > import random
> > #the above gives the program the ability to get a
> > #pseudo random number
> > file = open('test.rantxt')
> > listcontents = file.readlines()
> > #gives you the file as a list of records or it did
> on
> > #(assuming each line is a record)
> > file.close()
> > lenoflist = len(listcontents)-1
> > #find the length of the list and take one of
> because
> > computers count from 0
> 
> Yes, but len returns counting from 1.
> Anyway, you would have to add one to correct that
> anyway, wouldn't you?
As len(list) gives the length and when the elements of
the list are number for element 0 onwards, the last
element is number len(list) -1.   Test yourself
anyway.
Randrange does gives an integer or it did when I
tested this as otherwise it would have errored.
I don't know if it always does, what do other people
think ?
However Kent's idea of random.choice(list) is better
than my idea as it is one less line of code !!

.
If you have a length of 5
> If randrange is start <= x *<=* end, then you don't
> have to add one, you
> just use the length.
> If randrange is start<= x < end like __builtin__
> range, you have to put
> randrange(1,lenoflist+1)
> 
> > x = random.randrange(0,lenoflist)
> 
> I would use randint because list indices need to be
> integers -- unless of
> course I mistaken and
> randrange returns an integer also. (But that would
> be repetitive to have to
> functions do the same thing)
> 
> > print listcontents[x]
> 
> HTH,
> Jacob
> 
>  


	
	
		
___________________________________________________________ 
ALL-NEW Yahoo! Messenger - all new features - even more fun! http://uk.messenger.yahoo.com