CODEWITHSUNDEEP
bashshellunixawk
lyrically wicked
lyrically wicked

Reputation: 1417

How to concatenate corresponding columns from multiple files into one single file, using a specified column as ID?

If I have a number of files, such as

1.txt: 

1;ab, bc
2;cd, de, ef
3;fgh

2.txt: 

4;bc
1;cd, ef
5;ab
2;g

3.txt: 

5;ef, hl 
7;a, b, c
3;k, jk
1;b
6;x

Assuming that ; is a delimiter and the first column serves as ID, how to concatenate corresponding second columns (using eg. commas), so that the output becomes

output.txt: 

1;ab, bc, cd, ef, b
2;cd, de, ef, g
3;fgh, k, jk
4;bc
5;ab, ef, hl 
7;a, b, c
6;x

Upvotes: 0

Views: 86

Answers (2)

karakfa
karakfa

Reputation: 67507

awk to the rescue!

$ awk -F";" '{a[$1]=a[$1]?a[$1]","$2:$2} 
          END{for(k in a) print k";"a[k]}' file{1,2,3} | sort 

1;ab, bc,cd, ef,b
2;cd, de, ef,g
3;fgh,k, jk
4;bc
5;ab,ef, hl 
6;x
7;a, b, c

Upvotes: 2

oxnz
oxnz

Reputation: 875

cause join(1) is designed for join two files, and the input has to be sort, so why bother. the awk source:

#!/usr/bin/env awk -f

BEGIN { FS = ";" }
FNR==NR { a[$1] = $2; next}
{
    if ($1 in a) {
        a[$1] = a[$1] ", " $2
    } else {
        a[$1] = $2;
    }
}

END {
    for (i in a) {
        printf("%s%s%s\n", i,FS,a[i]);
    }
}

Upvotes: 0

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