AWK - Howto concatenate variable number of fields in a line

Author

Howto concatenate variable number of fields in a line

john coltrane

2007-02-01, 9:56 pm

I am parsing a comma delimited file where one of the fields has
imbedded commas. I know the field starts at the second field and ends
at the second to last field. I would like to concatenate those fields
into one field and print it.
How can I do this?

I thought something like

{ for( i = 1; i <= NF-2;i++){ $s = $s " " $i}}
this is obviously creates a string with duplicate substrings, this is
bad.
so how can I do this.

An example of what I want follows:

input:

123, one, two, three, four, five, 567, 890

output:

one two three four five

I can't use printf because the number of fields vary.

any help?

thanks

john

Ed Morton

2007-02-01, 9:56 pm

john coltrane wrote:
> I am parsing a comma delimited file where one of the fields has
> imbedded commas. I know the field starts at the second field and ends
> at the second to last field. I would like to concatenate those fields
> into one field and print it.
> How can I do this?

You need to start by saying the word "field" a few more times ;-).

>
> I thought something like
>
> { for( i = 1; i <= NF-2;i++){ $s = $s " " $i}}
> this is obviously creates a string with duplicate substrings, this is
> bad.

????

> so how can I do this.
>
> An example of what I want follows:
>
> input:
>
> 123, one, two, three, four, five, 567, 890
>
> output:
>
> one two three four five

I thought you wanted to go to the second-last field (567), not the
third-last (five).

> I can't use printf because the number of fields vary.

????

> any help?

I'm really not sure what you want, but maybe it's just:

$ echo "123, one, two, three, four, five, 567, 890" |
awk -F", " '{$1=$NF=$(NF-1)=""}1'
one two three four five

If not, please clarify and tell us which awk you use. There's various
ways to get rid of extra spaces if that's a problem.

Ed.

loki harfagr

2007-02-01, 9:56 pm

On Thu, 01 Feb 2007 13:52:47 -0600, Ed Morton wrote:

> john coltrane wrote:
>
> You need to start by saying the word "field" a few more times ;-).
>
>
> ????
>
>
....
> I'm really not sure what you want, but maybe it's just:
>
> $ echo "123, one, two, three, four, five, 567, 890" |
> awk -F", " '{$1=$NF=$(NF-1)=""}1'
> one two three four five

Ed. I really like this !-)
In a short while you've been exposing "different" solutions than you
used to `prone' "afore", I'd guess that's a side effect of the backlash
you may have had from working hard on the variations in
shootfoot-getline thesaurus you wrote recently ;D)
Beware, your scripts are slightly becoming even more jokeful
than mine used to try to be ;-)

>
> If not, please clarify and tell us which awk you use. There's various
> ways to get rid of extra spaces if that's a problem.

I understood the OP like it seems you did, that's probably bad
news for reality ...-)
Now I'd just suggest a more classical and less
interesting resoultion than yours but it has some advantages in
ease to read while blind ;D)

$ awk '{for(i=2;i<=NF-2;i++){a=a$i}; print a;a=""}' FS=,

$ echo "123, one, two, three, four, five, 567, 890
> 123, one, two, three, 567, 890
> 123, one, two, 567, 890
> 123, one, two, three, four, 567, 890
> " | awk '{for(i=2;i<=NF-2;i++){a=a$i}; print a;a=""}' FS=,
one two three four five
one two three
one two
one two three four

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