[Tutor] sorting and writing to data file

[Alan Gauld]

On 02/02/14 03:08, adrian wrote:

> Newbie here.  I have a data (.dat) file with integers (2,9,1,5,7,3,9) in
> it just as shown.

In your code below you use a hard coded list not a data file?

> lab3int=[2,9,1,5,7,3,9]
> lab3int.sort()
> print(lab3int)

So far so good.

> lab3int=open('lab3int.dat','w')

But now you've reassigned lab3int to the file object
so you threw away all your data. You need a separate
variable to store the file pointer.
Lets call it intFile...

> lab3int.write()

Would now become

intfile.write(<your data goes here>)

But your data is a sorted list of integers so you need
to  convert that to a string before you can write it
to a text file.

You need a loop such as

for item in lab3int:
     intFile.write( str(item) )

If you had a lot of data you might want to think
about adding some newlines when you write too...

hth
-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos