normalize my table according to my ranges

Question

I want to normalize all my table (not by column or row) according to the max and min of all table.

for ex:

in these whole table : max : 9 min: 0

so I want to normalize all these numbers between 0 and 9 to between 0 and 1!

Any helps?

Answer 1

The standard formula for such normalisation is

(xi - min(x))/(max(x) - min(x))

So for this data we can do

vals <- unlist(df)
max_val <- max(vals)
min_val <- min(vals)
df[] <- (vals - min_val)/(max_val - min_val)

df
#  column1 column2 column3
#1  0.1111  0.3333  1.0000
#2  0.2222  0.4444  0.6667
#3  0.3333  0.6667  0.3333
#4  0.4444  0.3333  0.1111
#5  0.5556  0.0000  0.7778

data

df <- data.frame(column1 = 1:5, column2 = c(3, 4, 6, 3, 0), 
                 column3 = c(9, 6, 3, 1, 7))