Re: delete columns csv file

r wrote:
> On Apr 17, 12:55 am, Janis Papanagnou <Janis_Papanag...@[EMAIL PROTECTED]
>
> wrote:
> 
>>It's good style (and a sign of respect for the people trying to help
>>you) to quote enough context to make any posting self-contained.
>>
> 
> Oops, sorry I didn't know of that convention, with this in mind...
> 
> Considering this file kindly published by EM:
> 
> awk -F, '
> NR==FNR {
>    if (NR>1)
>       for (i=1;i<=NF;i++)
>          if ($i"" != "0.0e0")
>             good[i]
>    next
> }
> 
> {  out=sep=""
>    for (i=1;i<=NF;i++) {
>        if (i in good)
>           out = out sep $i
>        sep=FS
>    } print out
> 
> }' file file
> 
> So far since last correspondence I've understood the 'if' and 'for'
> statements but not understood why 'good[i] is written

It means to memorize variable 'i' in a set[*] called 'good'. Later all
the indices 'i' are taken from the set in the for loop; if (i in good).

[*] N.b. technically it's no set but an associative array, but it is
used like a set.)

> The guide
> states that 'then' statement is optional, but I would expected
> something like:

Awk, as the C language, doesn't have an explicit 'then'; the syntax of
a conditional statement is

    if (condition)
       statement
    else
       statement

> 
> then [i]=good
> 
> I also understand the next statement and the '!' not boolean function,
> but so far haven't found an explanation for 'out'. Any help please?

'out' is the name of a variable that is populated with information.
Initially set to the empty string, out="", then in the loop there's
more information appended, the contents of the variable 'sep' and
the contents of field with number stored in variable 'i'.

Janis

> 
> Thanks,