String functions

Let's see how we can transform or convert strings using R.

The most relevant string examples are as follows:

• To know the number of characters in a string:

nchar(c)
## [1] 24

• To return the substring of x, originating at a particular character in x:

substring(c,4)
## [1] "s is our first string"

• To return the substring of x originating at one character located at n and ending at another character located at a place, m:

substring(c,1,4)
## [1] "This"

• To divide the string x into a list of sub chains using the delimiter as a separator:

strsplit(c, " ")
## [[1]]
## [1] "This"   "is"     "our"    "first"  "string"

• To check if the given pattern is in the string, and in that case returns true (or 1):

grep("our", c)
## [1] 1
grep("book", c)
## integer(0)

• To look for the first occurrence of a pattern in a string:

regexpr("our", c)
## [1] 9
## attr(,"match.length")
## [1] 3
## attr(,"index.type")
## [1] "chars"
## attr(,"useBytes")
## [1] TRUE

• To convert the string into lowercase:

tolower(c)
## [1] "this is our first string"

• To convert the string into capital letters:

toupper(c)
## [1] "THIS IS OUR FIRST STRING"

• To replace the first occurrence of the pattern by the given value with a string:

sub("our", "my", c)
## [1] "This is my first string"

• To replace the occurrences of the pattern with the given value with a string:

gsub("our", "my", c)
## [1] "This is my first string"

• To return the string as elements of the given array, separated by the given separator using paste(string,array, sep=“Separator”):

paste(c,"My book",sep=" : ")
## [1] "This is our first string : My book"