rowmatch: Row Matching

In ArcadeAntics/essentials: Essential Functions not Included in Base R

Row Matching

Description

rowmatch and row.match return a vector of the positions of (first) row matches of its first argument in its second.

%rowin% and %row.in% are more intuituve interfaces as binary operator, which return a logical vector indicating if there is a row match or not for its left operand.

Usage

rowmatch(x, table, nomatch = NA_integer_, incomparables = NULL)

x %rowin% table

row.match(x, table, nomatch = NA_integer_, incomparables = NULL)

## S4 method for signature 'data.frame,data.frame'
row.match(x, table, nomatch = NA_integer_, incomparables = NULL)

## S4 method for signature 'data.frame,ANY'
row.match(x, table, nomatch = NA_integer_, incomparables = NULL)

## S4 method for signature 'ANY,data.frame'
row.match(x, table, nomatch = NA_integer_, incomparables = NULL)

x %row.in% table

## specifically for row matching data frames
row.match.data.frame(x, table, nomatch = NA_integer_, incomparables = NULL)

Arguments

x	vector, matrix, array, data.frame or NULL: the row values to be matched.
table	vector, matrix, array, data.frame or NULL: the row values to be matched against.
nomatch	the value to be returned in the case when no row match is found. Note that it is coerced to integer.
incomparables	a vector, matrix, array or data.frame of rows that cannot be matched. Any row in x matching a value in this object is assigned the nomatch value. In match, FALSE is equivalent to NULL, the same is true here.

Details

%rowin% and %row.in% are currently defined as ⁠"%rowin%" <- function(x, table) rowmatch(x, table, nomatch = 0) > 0⁠ ⁠"%row.in%" <- function(x, table) row.match(x, table, nomatch = 0) > 0⁠

rowmatch is intended for matrix-like objects including vectors, matrices, and arrays. Data frames are coerced to arrays.

Similar to row.names being generic with rownames as the default method, row.match is generic with rowmatch as the default method.

row.match.data.frame is the method used for row.match when one of x, table and incomparables is a data frame. It is available incase you want to call it directly. Instead of coercing to arrays, it coerces to data frames.

That %rowin% and %row.in% never return NA makes them particularly useful in if conditions.

Value

A vector of the same length as the number of rows in x.

rowmatch and row.match: An integer vector giving the row position in table of the first row match if there is a row match, otherwise nomatch.

If the i-th row of x is found to equal the j-th row of table then the value returned in the i-th position of the return value is j, for the smallest possible j. If no match is found, the value is nomatch.

%rowin% and %row.in%: A logical vector, indicating if a row match was located for each row of x: thus the values are TRUE or FALSE and never NA.

ArcadeAntics/essentials documentation built on Nov. 7, 2024, 4:33 p.m.