R: Sort (order) a dataframe or matrix by multiple columns

dfOrder {psych} | R Documentation

## Sort (order) a dataframe or matrix by multiple columns

### Description

Although `order` will order a vector, and it is possible to order several columns of a data.frame by specifying each column individually in the call to order, `dfOrder` will order a dataframe by as many columns as desired.

### Usage

    dfOrder(object, columns)

### Arguments

`object` | The data.frame to be sorted
`columns` | Column numbers to use for sorting. If positive, then they will be sorted in increasing order. If negative, then in decreasing order

### Details

This is just a simple helper function to reorder data.frames. Originally developed to organize IRT output from the ltm package. It is a basic add on to the order function.

### Value

The original data frame is now in sorted order.

### Author(s)

William Revelle

### See Also

This code is used in the `test.irt` function to combine ltm and `sim.irt` output.

### Examples

    x <- data.frame(matrix(sample(1:4,64,replace=TRUE),ncol=4))
    dfOrder(x)  # sort by all columns
    dfOrder(x,c(1,4))  #sort by the first and 4th column
    dfOrder(x,c(1,-2))  #sort by the first in increaseing order,
       #the second in decreasing order

[Package psych version 1.7.3.21 Index]