Qu

standardize

Builtin index · Statistics & ML

result = standardize(X)

Input: X · Output: result

What it is

z-score scaling of X (vector, matrix column-wise, or table per numeric column): (x - mean) / std.

Overloads

X can be Vec, Mat, or matrix.

3 forms. Each carries its own inputs, outputs and worked example — pick the tab for the one you are calling.

CodeInputOutputDescription
result = standardize(X)
X Vecnot documented yet
result vector
A plain Vec is standardized as a whole -- one mean, one std, across every element.

Examples

Written for this form and run by the build -- the output below is what the engine actually produced.

sv = [2.0, 4.0, 6.0, 8.0]
print("standardize on a vector: {round(standardize(sv), 3)}")
output
standardize on a vector: [-1.162, -0.387, 0.387, 1.162]
CodeInputOutputDescription
result = standardize(X)
X Matnot documented yet
result vector
An N-row, D-column Mat is standardized column by column -- each column gets its own mean and std, independent of the others.

Examples

Written for this form and run by the build -- the output below is what the engine actually produced.

sm = [1.0, 100.0; 2.0, 200.0; 3.0, 300.0]
print("standardize on a matrix, per column: {round(standardize(sm), 3)}")
output
standardize on a matrix, per column: [-1, -1; 0, 0; 1, 1]
CodeInputOutputDescription
result = standardize(X)
X matrixnot documented yet
result vector
A table is standardized per numeric column, exactly like a matrix -- a non-numeric column (a label, say) passes through untouched instead of erroring.

Examples

Written for this form and run by the build -- the output below is what the engine actually produced.

st = table(a = [1.0, 2.0, 3.0], b = [10.0, 20.0, 30.0], label = ["x", "y", "z"])
print("standardize on a table, per numeric column (label untouched):")
print(standardize(st))
output
standardize on a table, per numeric column (label untouched):
 a   b  label
--  --  -----
-1  -1  x    
 0   0  y    
 1   1  z    

normalize, robust_scale and quantile_normalize all branch the same three ways.

How it works

standardize(X) — z-score: (x - mean) / std.

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.