Merge first 2 columns

Dracaena · 05-29-2018, 07:28 AM

Hi all,

I am stuck on a large file in which I would like to merge the first 2 columns and then save it as a new file.

example:

JTK 1 duck cat snake
JTK 2 pig cow owl
JTK 3 fox wolf chicken
JTK1 1 eagle godwit curlew
JTK1 2 bustard mouse lion

would then be:

JTK1 duck cat snake
JTK2 pig cow owl
JTK3 fox wolf chicken
JTK11 eagle godwit curlew
JTK12 bustard mouse lion

I have tried

Code:

awk -F, '{print $1$2"\t"$3"\t"$4"\t"$5}' file.txt

but it just rendered the same file.

Many thanks

rtmistler · 05-29-2018, 07:33 AM

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

I think it has to do with the field delimited, but cannot test that on a system.

syg00 · 05-29-2018, 07:34 AM

Why are you using "-F," ?.

Turbocapitalist · 05-29-2018, 07:38 AM

Yes, take out the Input Field Separator.

Code:

awk '{ print $1$2, 3, $4, $5; }' OFS='\t'

If you have more fields or a variable number of fields then you will need a slight modification to that with a for loop.

Guttorm · 05-29-2018, 07:56 AM

If the number of fields is not always 5, it gets a little more complicated. Also, that awk will change all spaces (1 or many tabs/spaces) into one tab.

Another way to look at it, is to delete the first space in every line of the file. If that's really all that's needed, you could use sed:

Code:

sed 's/ //' file.txt

syg00 · 05-29-2018, 08:06 AM

Column based data is generally better handled in awk - it even provides NF so you can loop over a (possibly indeterminate) number of fields.
If sed is to be used, better to use character classes to be safe.

Dracaena · 05-29-2018, 08:50 AM

Thanks for the help and suggestions!

AnanthaP · 05-30-2018, 05:15 AM

AnanthaP · 05-30-2018, 05:25 AM

Code:

awk '{
       n =split($0,a," "); 
       for(i=1;i<=n;i++) {
         printf("%s",a[i]) ;
         if( (i>1) && (i<n)) printf(" ") ;
       }
       printf("\n") ;
}'

OK