[Tutor] Problem on filtering data

[Steven D'Aprano]

On Mon, Jun 08, 2015 at 04:50:13PM +0200, jarod_v6--- via Tutor wrote:
> Dear All;
> I have a very silly problem.

The right way to handle CSV files is to use the csv module:

https://docs.python.org/2/library/csv.html
http://pymotw.com/2/csv/

Some more comments further below.


> with open("Dati_differenzialigistvsminigist_solodiff.csv") as p:
>     for i in p:
>         lines = i.strip("\n").split("\t")
>         if lines[8] != "NA":
>             if lines[8] :
>                 print lines[8]
> 
> Why I continue to obtain "" empity line?

I don't know. What do you mean 'obtain "" empty line'? Do you mean that 
every line is empty? Some of the lines are empty? One empty line at the 
end? How do you know it is empty? You need to explain more.

Perhaps put this instead:

    print repr(lines[8])

to see what it contains. Perhaps there are invisible s p a c e s so it 
only looks empty.

Some more comments:

In English, we would describe open("Dati....csv") as a file, and write 

    with open("Dati....csv") as f:  # f for file

I suppose in Italian you might say "archivio", and write:

    with open("Dati....csv") as a:

But what is "p"?

The next line is also confusing:

    for i in p:

"for i in ..." is used for loops over the integers 0, 1, 2, 3, ... and 
should not be used for anything else. Here, you loop over the lines in 
the file, so you should write:

    for line in p:
        fields = line.strip("\n").split("\t")

or perhaps "columns" instead of "fields". But "lines" is completely 
wrong, because you are looking at one line at a time.



-- 
Steve