Manipulating the awk output depending on the number of occurrences - awk

Question

I don't know how to word it well. I have an input file with the first column of each row being the index. I need to convert this input file into multi-columned output file so that starting indexes of each such columns match.
I have an input file in the following format:
1 11.32 12.55
1 13.32 17.55
1 56.77 33.22
2 34.22 1.112
3 12.13 13.14
3 12.55 34.55
3 22.44 12.33
3 44.32 77.44
The expected output should be:
1 11.32 12.55 2 34.22 1.112 3 12.13 13.14
1 13.32 17.55 3 12.55 34.55
1 56.77 33.22 3 22.44 12.33
3 44.32 77.44
Is there an easy way I can do this in awk?

Answer 1

Something like this, in bash:
paste <(grep '^1 ' input.txt) <(grep '^2 ' input.txt) <(grep '^3 ' input.txt)
paste has an option to set the delimiter if you don't want the default tab characters used, or you could post-process the tabs with expand...
EDIT: For an input file with many more tags, you could take this sort of approach:
awk '{print > "/tmp/output" $1 ".txt"}' input.txt
paste /tmp/output*.txt > final-output.txt
The awk line outputs each line to a file named after the first field of the line, then paste recombines them.
EDIT: as pointed out in a comment below, you might have issues if you end up with more than 9 intermediate files. One way around that would be something like this:
paste /tmp/output[0-9].txt /tmp/output[0-9][0-9].txt > final-output.txt
Add additional arguments as needed if you have more than 99 files... or more than 999... If that's the case, though, a python or perl solution might be a better route...

Answer 2

If all you need is independently running columns (without trying to line up matching items between the columns or anything like that) then the simplest solution might be something like:
awk '{print > $1".OUT"}' FILE; paste 1.OUT 2.OUT 3.OUT
The only issue with that is it won't fill in missing columns so you will need to fill those in yourself to line up your columns.
If the column width is known in advance (and the same for every column) then using:
paste 1.OUT 2.OUT 3.OUT | sed -e 's/^\t/ \t/;s/\t\t/\t \t/'
where those spaces are the width of the column should get you what you want. I feel like there should be a way to do this in a more automated fashion but can't think of one offhand.