Transpose one column to rows based on another column values - unix

Question

I want to transpose a column in several smaller parts based on another column's values e.g.
1 ID1 V1
2 ID1 V2
3 ID1 V3
4 ID2 V4
5 ID2 V5
6 ID3 V6
7 ID3 V7
8 ID3 V8
9 ID3 V9
I wish to have all V values for each ID to be in one row e.g.
ID1 V1 V2 V3
ID2 V4 V5
ID3 V6 V7 V8 V9
Each id has different number of rows to transpose as shown in the example. If it is easier to use the serial number column to perform this then that is fine too.
Can anyone help ?

Answer 1

Here is a simple awk one-liner to do the trick:
awk '1 {if (a[$2]) {a[$2] = a[$2]" "$3} else {a[$2] = $3}} END {for (i in a) { print i,a[i]}}' file.txt
Output:
ID1 V1 V2 V3
ID2 V4 V5
ID3 V6 V7 V8 V9

Answer 2

If you like coding in Javascript this is how to do it on the command line using jline: https://github.com/bitdivine/jline/
mmurphy#violet:~$ cat ,,, | jline-foreach 'begin::global.all={}' line::'fields=record.split(/ +/);if(fields.length==3)tm.incrementPath(all,fields.slice(1))' end::'tm.find(all,{maxdepth:1},function(path,val){console.log(path[0],Object.keys(val).join(","));})'
ID1 V1,V2,V3
ID2 V4,V5
ID3 V6,V7,V8,V9
where the input is:
mmurphy#violet:~$ cat ,,,
1 ID1 V1
2 ID1 V2
3 ID1 V3
4 ID2 V4
5 ID2 V5
6 ID3 V6
7 ID3 V7
8 ID3 V8
9 ID3 V9
mmurphy#violet:~$
Explanation: This builds a tree where the first level of branches is the user ID and the second is the V (version?). You could do this for any number of levels. The leaves are just counters. First we create an empty tree:
'begin::global.all={}'
Then each line that comes in is split into counter, ID and version number. The counter is sliced off leaving just the array [userID,version]. incrementCounter creates those branches in the tree, a bit like mkdir -p, and increments the leaf counter although you don't actually need to know how often each user,version combination has been seen:
line::'fields=record.split(/ +/);if(fields.length==3)tm.incrementPath(all,fields.slice(1))' end::'tm.find(all,{maxdepth:1},function(path,val){console.log(path[0],Object.keys(val).join(","));})'
At the end we have tm.find which behaves just like UNIX find and prints every path in the tree. Except that that we limit the depth of the search to the desired breakdown (1, but if you're like me you'll be wanting to do a breakdown of 2,3,5 or 8 variables next). That way you have separated out the breakdown and your list of values and you can print your answer.
If you are never going to need deeper breakdowns you will probably want to stick with awk, as it's probably preinstalled.