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Concatenate two columns in a file

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Top Forums Shell Programming and Scripting Concatenate two columns in a file
# 8  
Old 08-11-2014
Hello,

Could you please try the following for same.

Code:
awk -F, '{$(NF-1)=$(NF-1) $NF}; {a=(NF-1)} {if(NR==1){$(NF-1)="new column"}}  {if(NR==1){$NF="new column"}} {for(i=1;i<=(NF-1);i++){if(i%a==0){ORS="\n"; print $i}  else {ORS=","; print $i}}}' OFS="," filename

Output will be as follows.

Code:
COL1,COL2,new column
1,A,B,CD
2,e,f,gh


Thanks,
R. Singh
Last edited by RavinderSingh13; 08-11-2014 at 10:47 AM.. Reason: a small correction
# 9  
Old 08-11-2014
From Singh's code I have learnt a few things like OFS,ORS,NF,NR,FS

Thanks Singh.

@Bhaskar

In my previous code it is feasible if you have less number of columns. But what if you have more columns in your input file? It is difficult to enter all the numbers one by one in the code. That's why I have changed my code using the Singh's code and finally arrived with the output

Try this code
Code:
awk -F, '{for(i=1;i<=(NF-1);i++){if(i==(NF-1)){ORS="\n"; print $i$(i+1)}  else {ORS=","; print $i}}}' OFS=","  test250

Output:
Code:
Col1,Col2,Col3Col4
1,A,B,CD
2,e,f,gh


Note: Just change the first line of output in your text editor



Moderator's Comments:
Mod Comment Please wrap [CODE] & [/CODE] tags round code, input & output/errors to make them easier to read.
# 10  
Old 08-11-2014
Try also:
Code:
awk 'NR==1 {print $1, $2, "newcolumns"; next} {$4=$4$5;sub(","$5,"",$0)}1' FS=, OFS=, file
COL1,COL2,newcolumns
1,A,B,CD
2,e,f,gh

or, for more than 5 columns:
Code:
 awk 'NR==1 {print $1, $2, "newcolumns"; next} {$(NF-1)=$(NF-1)$NF;sub(","$NF,"",$0)}1' FS=, OFS=, file4
COL1,COL2,newcolumns
1,A,B,CD
2,e,f,gh

or, to make it even more versatile (for the header):
Code:
awk '{$(NF-1)=NR==1?hd:$(NF-1)$NF;sub(","$NF,"",$0)}1' FS=, OFS=, hd="newcolumns" file
COL1,COL2,newcolumns
1,A,B,CD
2,e,f,gh

Last edited by RudiC; 08-11-2014 at 09:48 AM..
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