awk - print range of fields

[Raynald Boucher]

Hello all,

I'm trying to rearrange a file where rows contain a variable number of fields.
How can I print "field 6 to end of line"?

example:
awk '{print $4 " " $2 " " $3 " " $6through$NF :'

Thanks
RayB

[A. Clay Stephenson · Accepted solution]

awk '{ printf("%s %s %s ",$4,$2,$3); i = 6; while (i < (NF - 1)) { printf("%s ",$i); ++i; } printf("%s\n",$NF); }'

[James R. Ferguson]

Hi:

# awk '{printf "%s %s %s ",$4,$2,$3;for (i=7;i
Regards!

...JRF...

[James R. Ferguson]

Hi (again):

Ooops! Initialize i=6 not i=7...

Regards!

...JRF...

[Sandman!]

awk '{
for(i=2;i<=NF;++i) {
if (i==2)
str=$i
else if (i==3)
str=str" "$i
else if(i==4)
str=$i" "str
else if (i==5)
printf("%s ",str)
else
printf(i }
}' infile

[Hein van den Heuvel]

In perl you can take a slice of an array with the x .. y notation.
The elements start at 0
A little to my surprise i coudl not use [5..-1] to indicate a slice from the 6th fields thru the end.

Anyway... a perl solution:


perl -alpe '$_ = join " ",@F[3,1,2,5..@F-1]' x.tmp

-a = autosplit into array @F
-l = add newline to print
-p = print $_ before looping
-e = here comes the program

Hein.

[Raynald Boucher]

Thanks all,
I had never thought of the loop.

I'll have to get a book or at least a quick ref.

Thanks again.
Rayb

[James R. Ferguson]

Hi:

> Hein: A little to my surprise i coudl not use [5..-1] to indicate a slice from the 6th fields thru the end.

Yes, but this would work:

# perl -alpe '$_ = join " ",@F[3,1,2,-4..-1]' x.tmp

Regards!

...JRF...

[Hein van den Heuvel]

Ray,

Sorry for this side line

And btw...
why not just TRY the perl solution.
It's just an other language/tool.

JRF,
>> # perl -alpe '$_ = join " ",@F[3,1,2,-4..-1]' x.tmp

Yes, the -n..-m does work but the start end end of the slice would both be relative to the end. So for example for 20 fields it would return 16 .. 20, not the desired 6 .. 20.

fwiw,
Hein.

[James R. Ferguson]

Hi:

Hein: > Yes, the -n..-m does work but the start end end of the slice would both be relative to the end. So for example for 20 fields it would return 16 .. 20, not the desired 6 .. 20.

Yes, I now see why you chose the approach you did.

Sandman: BTW, I had not thought of using conditional operators in 'awk'. That's very nice!

Regards!

...JRF...

[Raynald Boucher]

Hein and James,

Sometimes I'd like to try Perl but We don't use it except in some OS scripts and noboby in my shop is proficient.
It would become a maintenance problem.

Is there a -quick- way to learn Perl?
Which manual would you recommend?

Rayb

[James R. Ferguson]

Hi Raynald:

I'd probably start with "Learning Perl" from the O'Reilly publishers. A compendium of links to good stuff is:

http://perlmonks.org/index.pl?node_id=284175

Like any language, the best way to really learn it is to use it.

Regards!

...JRF...

[A. Clay Stephenson]

The learning curve for Perl is a bit steeper than with many other scripting languages but the rewards are also greater. It's one of the very few scripting languages that are widely portable. Well-written Perl scripts will run on any flavor of UNIX, Windows, MacOS, VMS, ... without change. Unlike most scripting languages, almost anything that can be done in C can also be done in Perl.

Perhaps the worst quality of Perl is also its best quality: the ability to pack an enormous amount of processing into one line. This characteristic makes it very easy to produce Perl code that is extremely cryptic especially for beginners. It's really quite easy to write Perl in a style that is verbose and clear; it's just not done that often. I suppose that it's one of those "suffering (or at least confusion) is good for the soul" things.

[Hein van den Heuvel]

Btw... if the contents of field $6 van not match fields $1 - $5, then a simple awk solution could be:

$ awk '{print $4,$2,$3,substr($0,index($0,$6))}' x.tmp

If $6 is a 'short' field then you can increase its uniqueness by pre end-or post pending a knwo separator:

$ awk '{print $4,$2,$3,substr($0,index($0," " $6 " "))}' x.tmp


Cheers,
Hein.

[Rodney Hills]

Maybe a better tools then awk would be "cut".

cut -f 4,2,3,6- inputfile >outputfile

cut assumes tab for the delimiter, but you can override with the -d option.

HTH

Rod Hills

[Dennis Handly]

>Rod: Maybe a better tools then awk would be "cut".

cut(1) is usually not a better tool than awk.
It has rigorous ideas of delimiters, if you have more than one between fields.

[Raynald Boucher]

Thanks again, closing thread.

[Raynald Boucher]

Closed!