# nPairs: Number of variable pairs In gdata: Various R Programming Tools for Data Manipulation

## Description

`nPairs` counts the number of pairs between variables.

## Usage

 `1` ```nPairs(x, margin=FALSE, names=TRUE, abbrev=TRUE, ...) ```

## Arguments

 `x` data.frame or a matrix `margin` logical, calculate the cumulative number of “pairs” `names` logical, add row/col-names to the output `abbrev` logical, abbreviate names `...` other arguments passed to `abbreviate`

## Details

The class of returned matrix is nPairs and matrix. There is a summary method, which shows the opposite information - counts how many times each variable is known, while the other variable of a pair is not. See examples.

## Value

Matrix of order k, where k is the number of columns in `x`. Values in a matrix represent the number of pairs between columns/variables in `x`. If `margin=TRUE`, the number of columns is k+1 and the last column represents the cumulative number of pairing all variables.

## Author(s)

Gregor Gorjanc

`abbreviate`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```## Test data test <- data.frame(V1=c(1, 2, 3, 4, 5), V2=c(NA, 2, 3, 4, 5), V3=c(1, NA, NA, NA, NA), V4=c(1, 2, 3, NA, NA)) ## Number of variable pairs nPairs(x=test) ## Without names nPairs(x=test, names=FALSE) ## Longer names colnames(test) <- c("Variable1", "Variable2", "Variable3", "Variable4") nPairs(x=test) ## Margin nPairs(x=test, margin=TRUE) ## Summary summary(object=nPairs(x=test)) ```