2. patsy.builtins

2.1. Functions

C(data[, contrast, levels]) Marks some data as being categorical, and specifies how to interpret it.
I(x) The identity function.
Q(name) A way to ‘quote’ variable names, especially ones that do not otherwise meet Python’s variable name rules.
bs(x[, df, knots, degree, ...]) Generates a B-spline basis for x, allowing non-linear fits.
cc(x[, df, knots, lower_bound, upper_bound, ...]) Generates a cyclic cubic spline basis for x (with the option of absorbing centering or more general parameters constraints), allowing non-linear fits.
center(x) A stateful transform that centers input data, i.e., subtracts the mean.
cr(x[, df, knots, lower_bound, upper_bound, ...]) Generates a natural cubic spline basis for x (with the option of absorbing centering or more general parameters constraints), allowing non-linear fits.
scale(*args, **kwargs) standardize(x, center=True, rescale=True, ddof=0)
standardize(x[, center, rescale, ddof]) A stateful transform that standardizes input data, i.e.
te(s1, .., sn[, constraints]) Generates smooth of several covariates as a tensor product of the bases of marginal univariate smooths s1, .., sn.
test_I()
test_Q()

2.2. Classes

ContrastMatrix(matrix, column_suffixes) A simple container for a matrix used for coding categorical factors.
Diff Backward difference coding.
Helmert Helmert contrasts.
Poly([scores]) Orthogonal polynomial contrast coding.
Sum([omit]) Deviation coding (also known as sum-to-zero coding).
Treatment([reference]) Treatment coding (also known as dummy coding).