Capitalizing letters. R equivalent of excel "PROPER" function [duplicate]

Question

Colleagues,

I'm looking at a data frame resembling the extract below:

Month   Provider Items
January CofCom   25
july    CofCom   331
march   vobix    12
May     vobix    0

I would like to capitalise first letter of each word and lower the remaining letters for each word. This would result in the data frame resembling the one below:

Month   Provider Items
January Cofcom   25
July    Cofcom   331
March   Vobix    12
May     Vobix    0

In a word, I'm looking for R's equivalent of the ROPER function available in the MS Excel.

Answer 1

The question is about an equivalent of Excel PROPER and the (former) accepted answer is based on:

proper=function(x) paste0(toupper(substr(x, 1, 1)), tolower(substring(x, 2)))

It might be worth noting that:

proper("hello world")
## [1] "Hello world"

Excel PROPER would give, instead, "Hello World". For 1:1 mapping with Excel see @Matthew Plourde.

If what you actually need is to set only the first character of a string to upper-case, you might also consider the shorter and slightly faster version:

proper=function(s) sub("(.)", ("\\U\\1"), tolower(s), pe=TRUE)

Answer 2

Another method uses the stringi package. The stri_trans_general function appears to lower case all letters other than the initial letter.

require(stringi)
x <- c('woRd Word', 'Word', 'word words')
stri_trans_general(x, id = "Title")
[1] "Word Word"  "Word"       "Word Words"

Answer 3

With regular expressions:

x <- c('woRd Word', 'Word', 'word words')
gsub("(?<=\\b)([a-z])", "\\U\\1", tolower(x), perl=TRUE)
# [1] "Word Word"  "Word"       "Word Words"

(?<=\\b)([a-z]) says look for a lowercase letter preceded by a word boundary (e.g., a space or beginning of a line). (?<=...) is called a "look-behind" assertion. \\U\\1 says replace that character with it's uppercase version. \\1 is a back reference to the first group surrounded by () in the pattern. See ?regex for more details.

If you only want to capitalize the first letter of the first word, use the pattern "^([a-z]) instead.