camr_match_and_assign: Assign New Values Based on Partial or Exact Matching

In rettopnivek/camrprojects: Portable Functions for R Projects at CAM-MGH

Assign New Values Based on Partial or Exact Matching

Description

A flexible function for matching old values and assigning new values based on matches. Can also assign new values based on whether old values fall within a range or interval of values.

Usage

camr_match_and_assign(
  x,
  values,
  new_values = NULL,
  type = "exact",
  default = NA,
  replace_if = NULL
)

Arguments

x	Either (a) a vector of values to match over, or (b) a data frame with columns to match over.
values	Either (a) a vector of values to match against, or (b) a named list with values to match against. If matching over multiple columns in a data frame, the names for the elements of values must equal the column names to match against. Optionally, the user can also include an element named new_values.
new_values	A vector of new values to assign based on matches to elements from values (vector must be of equivalent length to values or the elements of values). Note if this argument is not supplied, then the argument values must contain an element new_values.
type	The type of matching, either 'exact' (cases for x and values must match exactly), 'partial' (cases for x must contain values in some form), 'greater than' (lower boundary > x \leq upper boundary) or 'less than' (lower boundary \geq x < upper boundary). 'partial' or 'exact' (uses grepl or ⁠\%in\%⁠, respectively).
default	Either a single value to assign in the absence of a match, or a vector equivalent in length to x.
replace_if	An optional vector specifying the subset of default values when it is appropriate to assign new values.

Value

A new vector of equivalent length to x, with values assigned based on successful matches.

Author(s)

Kevin Potter

Examples

# Replace letters with numbers
x <- rep( c("A", "B", "C" ), each = 2 )
camr_match_and_assign(
x,
  c( "A", "B", "C" ),
  new_values = 1:3
)

# Alternative formats for input

# As single list with both old and new values
camr_match_and_assign(
  x,
  list( x = c( "A", "B", "C" ), new_values = 1:3 )
)

# Converting matrix to data frame
camr_match_and_assign(
  x,
  rbind(
    c( "A", "1" ),
    c( "B", "2" ),
    c( "C", "3" )
  ) |> data.frame() |> setNames( c("x", "new_values" ) )
)

# Can restrict subset of entries
# over which replacement occurs;
# replace odd-numbered rows
camr_match_and_assign(
  x,
  c( "A", "B", "C" ),
  new_values = 1:3,
  default = x, # Can pass vector as default
  replace_if = seq_along( x ) %in% c( 1, 3, 5 )
)

# Can base on partial matching
x <- rep( c("AD", "BE", "CF" ), each = 2 )
camr_match_and_assign(
  x,
  c( "A", "B", "C" ),
  new_values = 1:3,
  type = 'partial'
)

# Can match over range or interval of values
set.seed( 112 )
x <- rnorm( 10 )
camr_match_and_assign(
  x,
  list(
    lower = c(    -Inf,  -1,    1 ),
    upper = c(      -1,   1,  Inf ),
    new_values = c( "A", "B", "C" )
  ),
  new_values = c( "A", "B", "C" ),
  type = 'greater than'
)

rettopnivek/camrprojects documentation built on March 26, 2024, 9:17 a.m.