update.list: Update the elements of a list, or rows of a data frame

Description

For a list, update the elements of a list to contain all of the named elements of a new list, overwriting elements with the same name, and (optionally) copying unnamed elements. For a data frame, replace the rows of a data frame by corresponding rows in 'new' with the same value for 'by'.

Usage

# S3 method for list
update(object, new, unnamed=FALSE, ...)
# S3 method for data.frame
update(object, new, by, by.x=by, by.y=by,
       append=TRUE, verbose=FALSE, ...)

Value

update.list: a list a constructed from the elements of object, with named elements of new replacing corresponding named elements from object, and non-corresponding elements of new appended. If unnamed=TRUE, unnamed elements of new will be appended.
update.data.frame: a data frame constructed from the rows of object with rows where values in by.x equal the values in by.y replaced by the corresponding row in new. If append=TRUE, any elements of new without no matching rows in object will be appended.

Arguments

object: List or data frame to be updated.
new: List or data frame containing new elements/rows.
unnamed: Logical. If TRUE, unnamed list elements of new will be appended to object.
by, by.x, by.y: Character. Name of column to use for matching data frame rows.
append: Logical. If TRUE, items in new with no match in object will be appended to the data frame.
verbose: Logical. If TRUE progress messages will be displayed.
...: optional method arguments (ignored).

Author

Gregory R. Warnes greg@warnes.net

Examples

Run this code

# Update list
old <- list(a=1,b="red",c=1.37)
new <- list(b="green",c=2.4)

update(old, new)
update.list(old,new)  # equivalent

older <- list(a=0, b="orange", 4, 5, 6)
newer <- list(b="purple", 7, 8, 9)
update(older, newer)               # ignores unnamed elements of newer
update(older, newer, unnamed=TRUE) # appends unnamed elements of newer

# Update data frame
old <- data.frame(letter=letters[1:5], number=1:5)
new <- data.frame(letter=letters[c(5, 1, 7)], number=c(-5, -1, -7))

update(old, new, by="letter") # default is append=TRUE
update(old, new, by="letter", append=FALSE)
update(old, new, by="letter", verbose=FALSE)