Min-Max Normalization using AWK - bash

Question

I dont know Why I am unable to loop through all the records. currently it goes for last record and prints the normalization for it.
Normalization formula:
New_Value = (value - min[i]) / (max[i] - min[i])
Program
{
for(i = 1; i <= NF; i++)
{
if (min[i]==""){ min[i]=$i;} #initialise min
if (max[i]==""){ max[i]=$i;} #initialise max
if ($i<min[i]) { min[i]=$i;} #new min
if ($i>max[i]) { max[i]=$i;} #new max
}
}
END {
for(j = 1; j <= NF; j++)
{
normalized_value[j] = ($j - min[j])/(max[j] - min[j]);
print $j, normalized_value[j];
}
}
Dataset
4 14 24 34
3 13 23 33
1 11 21 31
2 12 22 32
5 15 25 35
Current Output
5 1
15 1
25 1
35 1
Required Output
0.75 0.75 0.75 0.75
0.50 0.50 0.50 0.50
0.00 0.00 0.00 0.00
0.25 0.25 0.25 0.25
1.00 1.00 1.00 1.00

Answer 1

I would process the file twice, once to determine the minima/maxima, once to calculate the normalized values:
awk '
NR==1 {
for (i=1; i<=NF; i++) {
min[i]=$i
max[i]=$i
}
next
}
NR==FNR {
for (i=1; i<=NF; i++) {
if ($i < min[i]) {min[i]=$i}
else if ($i > max[i]) {max[i]=$i}
}
next
}
{
for (i=1; i<=NF; i++) printf "%.2f%s", ($i-min[i])/(max[i]-min[i]), FS
print ""
}
' file file
# ^^^^ ^^^^ same file twice!
outputs
0.75 0.75 0.75 0.75
0.50 0.50 0.50 0.50
0.00 0.00 0.00 0.00
0.25 0.25 0.25 0.25
1.00 1.00 1.00 1.00

Answer 2

The given answer uses same file to be loaded twice, this can be avoided with following modified script:
# initialization on min, max and value array to be used later
NR == 1 {
for (i=1; i<=NF; i++) {
value[i] = $i
min[i] = $i
max[i] = $i
}
}
# finding min and max for each column
NR > 1 {
for (i=1; i<=NF; i++) {
value[((NR-1)*NF)+i] = $i
if ($i < min[i]) {min[i] = $i}
else if ($i > max[i]) {max[i] = $i}
}
}
END {
nrows = NF
ncolumns = NR
for (i=0; i<(ncolumns); i++ ) {
for (j=1; j<(nrows); j++ ) {
printf "%.2f%s", (value[(i*nrows)+j]-min[j])/(max[j]-min[j]), OFS
}
printf "%.2f\n", (value[(i*nrows)+j]-min[j])/(max[j]-min[j])
}
}
Save the above awk script as norm.awk. You can run this from shell (and redirect if needed) as:
awk -f norm.awk data.txt > norm_output.txt
or you can run this norm.awk script from vim itself as:
:%!awk -f norm.awk
Which will replace the existing values with min-max normalized values.