Reshape table and complete voids with NA (or -999) using bash - bash

Question

I'm trying to create a table based on the ASCII bellow. What I need is to arrange the numbers from the 2nd column in a matrix. The first and third columns of the ASCII give columns and rows in the new matrix. The new matrix needs to be fully populated, so it is necessary to complete missing positions on the new table with NA (or -999).
This is what I have
$ cat infile.txt
1 68 2
1 182 3
1 797 4
2 4 1
2 70 2
2 339 3
2 1396 4
3 12 1
3 355 3
3 1854 4
4 7 1
4 85 2
4 333 3
5 9 1
5 68 2
5 182 3
5 922 4
6 10 1
6 70 2
and what I would like to have:
NA 4 12 7 9 10
68 70 NA 85 68 70
182 339 355 333 182 NA
797 1396 1854 NA 922 NA
I can only use standard UNIX commands (e.g. awk, sed, grep, etc).
So What I have so far...
I can mimic a 2d array in bash
irows=(`awk '{print $1 }' infile.txt`) # rows positions
jcols=(`awk '{print $3 }' infile.txt`) # columns positions
values=(`awk '{print $2 }' infile.txt`) # values
declare -A matrix # the new matrix
nrows=(`sort -k3 -n in.txt | tail -1 | awk '{print $3}'`) # numbers of rows
ncols=(`sort -k1 -n in.txt | tail -1 | awk '{print $1}'`) # numbers of columns
nelem=(`echo "${#values[#]}"`) # number of elements I want to pass to the new matrix
# Creating a matrix (i,j) with -999
for ((i=0;i<=$((nrows-1));i++)) do
for ((j=0;j<=$((ncols-1));j++)) do
matrix[$i,$j]=-999
done
done
and even print on the screen
for ((i=0;i<=$((nrows-1));i++)) do
for ((j=0;j<=$((ncols-1));j++)) do
printf " %i" ${matrix[$i,$j]}
done
echo
done
But when I tried to assign the elements, something gets wrong
for ((i=0;i<=$((nelem-1));i++)) do
matrix[${irows[$i]},${jcols[$i]}]=${values[$i]}
done
Thanks in advance for any help with this, really.

Answer 1

A solution in plain bash by simulating a 2D array with an associative array could be something like that (Notice that row and column counts are not hard coded and the code works with any permutation of input lines provided that each line has the format specified in the question):
$ cat printmat
#!/bin/bash
declare -A mat
nrow=0
ncol=0
while read -r col elem row; do
mat[$row,$col]=$elem
if ((row > nrow)); then nrow=$row; fi
if ((col > ncol)); then ncol=$col; fi
done
for ((row = 1; row <= nrow; ++row)); do
for ((col = 1; col <= ncol; ++col)); do
elem=${mat[$row,$col]}
if [[ -z $elem ]]; then elem=NA; fi
if ((col == ncol)); then elem+=$'\n'; else elem+=$'\t'; fi
printf "%s" "$elem"
done
done
$ ./printmat < infile.txt prints out
NA 4 12 7 9 10
68 70 NA 85 68 70
182 339 355 333 182 NA
797 1396 1854 NA 922 NA

Answer 2

Any time you find yourself writing a loop in shell just to manipulate text you have the wrong approcah. See why-is-using-a-shell-loop-to-process-text-considered-bad-practice for many of the reasons why.
Using any awk in any shell on every UNIX box:
$ cat tst.awk
{
vals[$3,$1] = $2
numRows = ($3 > numRows ? $3 : numRows)
numCols = $1
}
END {
OFS = "\t"
for (rowNr=1; rowNr<=numRows; rowNr++) {
for (colNr=1; colNr<=numCols; colNr++) {
val = ((rowNr,colNr) in vals ? vals[rowNr,colNr] : "NA")
printf "%s%s", val, (colNr < numCols ? OFS : ORS)
}
}
}
.
$ awk -f tst.awk infile.txt
NA 4 12 7 9 10
68 70 NA 85 68 70
182 339 355 333 182 NA
797 1396 1854 NA 922 NA

Answer 3

here is one way to get you started. Note that this is not intended to be "the" answer but to encourage you to try to learn the toolkit.
$ join -a1 -e NA -o2.2 <(printf "%s\n" {1..4}"_"{1..6}) \
<(awk '{print $3"_"$1,$2}' file | sort -n) |
pr -6at
NA 4 12 7 9 10
68 70 NA 85 68 70
182 339 355 333 182 NA
797 1396 1854 NA 922 NA
works, however, row and column counts are hard coded, which is not the proper way to do it.
Preferred solution will be filling up an awk 2D array with the data and print it in matrix form at the end.