[Tutor] Two questions

[Lloyd Kvam]

You need to create a (possibly empty) list before you can stick
something into the list.  This should fix your problem:
i = 0
site_url = []	# create an empty list
site_url[i] = fileobject.readline()
print "site_url = ", site_url[i]

It is usually simpler to not track the positions when putting
things into the list.  Something like:

site_url = []
site_url.append( fileobject.readline())

simply adds the url to the end of the list.  You can NOT add
things to a tuple.  A tuple can NOT be changed.  If you want your
URLs to be in a tuple, create the list first.  Then use the
builtin tuple function.

tuple_site_url = tuple( site_url)	# makes tuple from list

Henry Steigerwaldt wrote:

> To Whom It May Concern:
> 
>  
> 
> The program I am about to describe is opened in Idle, and then run in
> 
> Idle. The code pieces below are all located in a function called Main().
> 
>  
> 
> The following piece of code works just fine:
> 
>  
> 
>    # read first line in a file to get URL
> 
>    site_url = fileobject.readline()
> 
>    print "site_url = ", url
> 
>  
> 
> In the above code, the URL read in first line of a file stores just fine
> 
> into variable "site_url." However, when I try to store the URL into a 
> 
> list or tuple, I get an error.
> 
>  
> 
> Below is the piece of code to store URL into a list:
> 
>  
> 
>    i = 0
> 
>    site_url[i] = fileobject.readline()
>    print "site_url = ", site_url[i]
> 
> Here is the error that is output in Idle:
> 
>  
> 
>   Main()
>   File "C:\python_pgms\misc_obs_pgm.py", line 37, in Main
>     site_url[i] = fileobject.readline()
> NameError: global name 'site_url' is not defined
> 
> _________________________________
> 
> Below is the piece of code to store URL into a tuple:
> 
>  
> 
>    i = 0
> 
>    site_url(i) = fileobject.readline()
>    print "site_url = ", site_url(i)
> 
>  
> 
> Here is the error that is output in Idle:
> 
>  
> 
>  File "C:\python_pgms\misc_obs_pgm.py", line 37
>     site_url(i) = fileobject.readline()
> SyntaxError: can't assign to function call
> ______________________________________________
> 
>  
> 
> I do not understand why I am getting these errors.
> 
>  
> 
> Actually what I want to do in this program is read the first
> 
> line of a file, which contains a number, say 4. The number tells
> 
> the program how many URLs will follow (one per line) in the file.
> 
> So after the first line of the file is read, the program then is
> 
> supposed to read and then store the URLs in either a list or
> 
> a tuple. After that, I want to go to each site (URL) and grab
> 
> some information.
> 
>  
> 
> Please be as least cryptic as possible in any response. I have
> 
> written some small programs in Tcl/Tk (and a couple of other
> 
> languages in the past), but my programming experience is very
> 
> limited.
> 
>  
> 
> Thanks for any help provided !
> 
>  
> 
> Henry Steigerwaldt
> 
> Hermitage, TN
> 
>  
> 


-- 
Lloyd Kvam
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