Standardize Columns

Problem

Standardize each column of data to zero mean and unit sample variance (denominator n - 1).

If a column has zero variance, output 0.0 for every entry in that column. Return a list of rows of floats.

Hint

Divide the centered values by the sample standard deviation.

case 1

in: [[[1,2],[3,4],[5,6]]]

expected: [[-1,-1],[0,0],[1,1]]

case 2

in: [[[1,10],[2,20],[3,30]]]

expected: [[-1,-1],[0,0],[1,1]]

case 3

in: [[[5,5],[5,5]]]

expected: [[0,0],[0,0]]

case 4

in: [[[1,0],[0,1]]]

expected: [[0.7071067811865475,-0.7071067811865475],[-0.7071067811865475,0.7071067811865475]]

Starter codePython

def standardize_columns(data):
    # Your code here
    pass

4 test cases · run your code against them in the editor