R String Functions

R string functions include substr(x), nchar(x), toupper(x), tolower(x), strsplit(x,y),paste(...), and regular expression functions sub(...), grep(...) etc.

>s <- "EndMemo.com R Language Tutorial"
[1] "EndMemo"

Get string length:
[1] 31

To uppercase:
>x <- toupper(s)

To lowercase:
>x <- tolower(s)
[1] "endmemo.com r language tutorial"

Split the string at letter "o":
>x <- strsplit(s,"o")
[1] "EndMem"           ".c"               "m R Language Tut" "rial"

Concatenate two strings:
>x <- paste(x," -- String Functions",sep="")
[1] "endmemo.com r language tutorial -- String Functions"

Substring replacement:
>x <- sub("Tutorial","Examples",s)
[1] "EndMemo.com R Language Examples"

Use regular expression:
>x <- sub("n.+e","XXX",s)
[1] "EXXX Tutorial"

Please see grep() function for more regular expression handling of string.