Hi Unix.com !

I would need some help for something I don't understand

input:

111|2 Y Z blue.
333|4 W X blue.; 5 Y Z red.
666|7 W X red.; 8 Y Z blue.
999|10 U V red.; 11 W X blue.; 12 Y Z red.

111|2 Y Z blue.|
333|4 W X blue.; 5 Y Z red.|5 Y Z red.
666|7 W X red.; 8 Y Z blue.|7 W X red.
999|10 U V red.; 11 W X blue.; 12 Y Z red.|10 U V red.; 12 Y Z red.

BEGIN{FS=OFS="|"}

NR==1{
          $3 = "Field3"
          }
NR>1{

    $3 = $2
	
    y = split($3,x,"; ")
        for (i=1; i<=y; i++){
        	
            if (x[i] ~ /blue/ && y=1){
            	$3 = gensub(x[i],"","g",$3)
        	}
        	
            else if (x[i] ~ /blue/ && i<y)
            	$3 = gensub(x[i]"; ","","g",$3)
            
            else if (x[i] ~ /blue/ && i=y)
                $3 = gensub("; "x[i],"","g",$3)
        }
        
    
}1

Field1|Field2|Field3
111|2 Y Z blue.|
333|4 W X blue.; 5 Y Z red.|; 5 Y Z red.
666|7 W X red.; 8 Y Z blue.|7 W X red.; 
999|10 U V red.; 11 W X blue.; 12 Y Z red.|10 U V red.; ; 12 Y Z red.

Hi beca123456,

One way:

$ cat infile
111|2 Y Z blue.
333|4 W X blue.; 5 Y Z red.
666|7 W X red.; 8 Y Z blue.
999|10 U V red.; 11 W X blue.; 12 Y Z red.
$ cat script.awk
BEGIN {
        FS = OFS = "|";
}

{
        split( $2, f, /;/ );
        for ( i = 1; i <= length( f ); i++ ) {
                if ( match( f[i], /blue/ ) >  0 ) {
                        continue;
                }
                $3 = $3 ( $3 ? ";" : "" ) f[i];
        }

        print $0;
}
$ awk -f script.awk infile
111|2 Y Z blue.
333|4 W X blue.; 5 Y Z red.| 5 Y Z red.
666|7 W X red.; 8 Y Z blue.|7 W X red.
999|10 U V red.; 11 W X blue.; 12 Y Z red.|10 U V red.; 12 Y Z red.

Thanks birei, works great !

Although, I have a question. I am not sure I understand this part:

$3 = $3 ( $3 ? ";" : "" ) f[i]

$3 = $3 ( $3 ? ";" : "" ) f[i]

f[i] gets added because that needed to get added in the first place, the part in parentheses is just to determine if a ";" should be put in between.

Alternative version:

awk -F'[|]|; ' '{s=""; for(i=2;i<=NF;i++) if($i!~/blue/) s=s (s?"; ":"") $i; print $0"|"s}' infile

Thanks Scrutinizer !

I get it now.