Question

I would like to split a vector of names:

names <- c("DOE John", "VAN DYKE Dick", "SMITH Mary Jane") 

into two vectors

last <- c("DOE", "VAN DYKE", "SMITH") 

and

first <- c("John", "Dick", "Mary Jane")

Any help would be greatly appreciated. Thanks.

Answer 1

This should work:

# Define a pattern that only matches words composed entirely of capital letters
pat <- paste("^[", paste(LETTERS, collapse=""), "]*$", sep="")
# [1] "^[ABCDEFGHIJKLMNOPQRSTUVWXYZ]*$"

names <- c("DOE John", "VAN DYKE Dick", "SMITH Mary Jane") 
splitNames <- strsplit(names, " ")

# LAST NAMES: (Extract and paste together words matching 'pat')
sapply(splitNames, 
       function(X) paste(grep(pat, X, value=TRUE), collapse=" "))
# [1] "DOE"      "VAN DYKE" "SMITH" 

# First Names: (Extract and paste together words NOT matching 'pat')
sapply(splitNames, 
       function(X) paste(grep(pat, X, value=TRUE, invert=TRUE), collapse=" "))
# [1] "John"      "Dick"      "Mary Jane"

To match all upper case letters, you could alternatively use the character class [:upper:], as in:

pat <- "^[[:upper:]]*$"

although the documentation at ?regexp seems to mildly warn against doing so, on grounds of reduced portability.