matching | R Documentation |
This function computes the simple matching distance from two data frames/ matrices.
matching(x, y)
x |
A first data frame or matrix (see Details). |
y |
A second data frame or matrix (see Details). |
The x
and y
arguments have to be data frames/
matrices with the same number of columns where the row indicates the object
and the column is the variable. This function calculates all pairwise
distance between rows in the x
and y
data frames/ matrices.
If the x
data frame/ matrix is equal to the y
data frame/
matrix, it explicitly calculates all distances in the x
data frame/
matrix.
The simple matching distance between objects i and j is calculated by
d_{ij} = \frac{∑_{s=1}^{P}(x_{is}-x_{js})}{P}
where P is the number of variables, and x_{is}-x_{js} \in {0, 1}. x_{is}-x_{js} = 0, if x_{is}=x_{js} and x_{is}-x_{js} = 1, when x_{is} \neq x_{js}.
As an example, the distance between objects 1 and 2 is presented.
object | x | y | z |
1 | 1 | 2 | 2 |
2 | 1 | 2 | 1 |
The distance between objects 1 and 2 is
d_{12} = \frac{∑_{s=1}^{3}(x_{is}-x_{js})}{3} = \frac{0 + 0 + 1}{3} = \frac{1}{3} = 0.33
Function returns a distance matrix with the number of rows equal to
the number of objects in the x
data frame/ matrix (n_x) and
the number of columns equals to the number of objects in the y
data frame/ matrix (n_y).
Weksi Budiaji
Contact: budiaji@untirta.ac.id
set.seed(1) a <- matrix(sample(1:2, 7*3, replace = TRUE), 7, 3) matching(a, a)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.