Make all records with the same number of fields (awk)


 
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# 1  
Make all records with the same number of fields (awk)

Hi,

input:
Code:
AA|BB|CC
DD|EE
FF

what I am trying to get:
Code:
AA|BB|CC
DD|EE|
FF||

I tried to create first an UDF for printing repeats, but I think I have an issue with my END section or my array:
Code:
function repeat(str, n, rep, i)
{
   for(i=1 ;i<n;i++)
      rep=rep str
      return rep
}

BEGIN{FS=OFS="|"}
{
   a[NR]=$0
   if(NF>max){
      max=NF}
}

END{
   for(i in a){
      if(NF<max){
         x=(max-NF)
         print a[i] repeat("|",x)}
      else{
         print a[i]}
   }
}

With this code it adds the same number of "|" no matter the number of fields the record contains:
Code:
AA|BB|CC|
DD|EE|
FF|

NOTE: I am using gawk (just in case I would have missed a built-in function for printing repeats)

Last edited by beca123456; 06-30-2015 at 03:19 PM..
# 2  
Try:
Code:
awk -F\| '{NF=3}1' OFS=\| file

# 3  
Try:
Code:
awk -v n=3 '{$n=$n}1' FS=\| OFS=\| file





--
Quote:
Originally Posted by Yoda
Try:
Code:
awk -F\| '{NF=3}1' OFS=\| file

Setting NF works with gawk and mawk, but not every awk recomputes the record the NF variable. Forcing a recompute with $1=$1 after setting NF works sometimes..

Last edited by Scrutinizer; 07-01-2015 at 12:48 AM..
# 4  
To be little more flexible, you can store the max number of columns in a variable first

Code:
nmaxcol=$(awk -F\|  '{if (NF > max) max = NF} END{print max}' file )

and then pass this variable to any of the above mentioned awk one liners.

Code:
awk -v n=$nmaxcol  '{$n=$n}1' FS=\| OFS=\| file

Even better, if your file is not too large, this might work too

Code:
awk -F\|  'NR==FNR{ if (NF > max) { max = NF }; next } { $max=$max}1' OFS=\| file file


Last edited by senhia83; 06-30-2015 at 05:33 PM..
# 5  
Try also
Code:
awk -F\|  '{T[NR]=$0; MAX=(NF>MAX)?NF:MAX} END {for (i=1; i<=NR; i++) {$0=T[i]; $MAX=$MAX; print}}' OFS=\| file
AA|BB|CC
DD|EE|
FF||

This User Gave Thanks to RudiC For This Post:
# 6  
Thanks RudiC !

@Yoda & Scrutinizer: I assumed that max NF was unknown.
@senhia83: it works, but RudiC's one is more concise.
# 7  
Just for fun...
Code:
awk 'NF>n{n=NF}{$n=$n}NR>FNR' FS=\| OFS=\| file file


Last edited by Scrutinizer; 07-01-2015 at 02:08 PM..
 

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