select_rows_cols_byname: Select (or deselect) rows or columns

In matsbyname: An Implementation of Matrix Mathematics that Respects Row and Column Names

Select (or deselect) rows or columns

Description

Arguments indicate which columns are to be retained and which are to be removed by routing to select_rows_byname() or select_cols_byname() based on the value of margin. margin can be a string or vector of strings that are matched to row and column types.

Usage

select_rows_cols_byname(
  a,
  margin = c(1, 2),
  retain_pattern = "$^",
  remove_pattern = "$^",
  ignore.case = FALSE,
  perl = FALSE,
  fixed = FALSE,
  useBytes = FALSE
)

Arguments

a	A matrix or a list of matrices.
margin	1 for rows, 2 for columns, or c(1, 2) (the default) for both. Can be a string or vector of strings that indicate row and/or column types.
retain_pattern	An extended regex or list of extended regular expressions that specifies which columns of m to retain. Default pattern ("$^") retains nothing.
remove_pattern	An extended regex or list of extended regular expressions that specifies which columns of m to remove. Default pattern ("$^") removes nothing.
ignore.case, perl, fixed, useBytes	Arguments passed to grep().

Details

If a is NULL, NULL is returned.

For maximum flexibility, arguments can be extended regex patterns that are matched against row or column names. If no row or column (depending on margin) names of a match the retain_pattern, NULL is returned. If no row or column (depending on margin) names of a match the remove_pattern, a is returned.

Retaining takes precedence over removing, always.

Some typical patterns are:

• "^Electricity$|^Oil$": row or column names that are EXACTLY "Electricity" or "Oil".

• "^Electricity|^Oil": row or column names that START WITH "Electricity" or "Oil".

• "Electricity|Oil": row or column names that CONTAIN "Electricity" or "Oil" anywhere within them.

If the row or column labels contain "[" or "]", care should be taken to escape those characters. Hmisc::escapeRegex() is helpful in such situations. This function assumes that retain_pattern and remove_pattern have already been suitably escaped.

Given a list of row or column names, a pattern can be constructed easily using RCLabels::make_or_pattern(). RCLabels::make_or_pattern() escapes regex strings using Hmisc::escapeRegex().

Note that the default retain_pattern and remove_pattern ("$^") retain nothing and remove nothing.

Note that if all columns are removed from a, NULL is returned.

Value

A matrix that is a subset of a with columns selected by retain_pattern and remove_pattern.

Examples

m <- matrix(1:16, ncol = 4, dimnames=list(c(paste0("i", 1:4)), paste0("p", 1:4))) |> 
  setrowtype("Industries") |> setcoltype("Commodities")
select_rows_cols_byname(m, 
                        margin = 2, # for columns
                        retain_pattern = RCLabels::make_or_pattern(c("p1", "p4"), 
                        pattern_type = "exact"))
select_rows_cols_byname(m, 
                        margin = 2, 
                        remove_pattern = RCLabels::make_or_pattern(c("p1", "p3"), 
                        pattern_type = "exact"))
# Also works for lists and data frames
select_rows_cols_byname(list(m,m), margin = 2, 
                        retain_pattern = "^p1$|^p4$")

matsbyname documentation built on June 8, 2025, 10:08 a.m.