VertexFrame correlation

---

correlation(self, data_column_names)

Calculate correlation for two columns of current frame.

Parameters:

data_column_names : list

The names of 2 columns from which to compute the correlation.

Returns:

: float64

Pearson correlation coefficient of the two columns.

This method applies only to columns containing numerical data.

Examples

Consider Frame my_frame, which contains the data

>>> my_frame.inspect()
[#]  idnum  x1   x2   x3   x4
===============================
[0]      0  1.0  4.0  0.0  -1.0
[1]      1  2.0  3.0  0.0  -1.0
[2]      2  3.0  2.0  1.0  -1.0
[3]      3  4.0  1.0  2.0  -1.0
[4]      4  5.0  0.0  2.0  -1.0

my_frame.correlation computes the common correlation coefficient (Pearson’s) on the pair of columns provided. In this example, the idnum and most of the columns have trivial correlations: -1, 0, or +1. Column x3 provides a contrasting coefficient of 3 / sqrt(3) = 0.948683298051 .

>>> my_frame.correlation(["x1", "x2"])
[===Job Progress===]

-1.0

>>> my_frame.correlation(["x1", "x4"])
[===Job Progress===]

0.0

>>> my_frame.correlation(["x2", "x3"])
[===Job Progress===]

-0.948683298051