All About Strings

Creating Character Strings

In R, we can express character strings by surrounding text with double quotes:

“learning is fun”,

or we can also surround text with single quotes:

‘learning is fun’.

Empty String

The most basic type of string is the empty string produced by consecutive quotation marks: "".

"" is a string with no characters in it, hence the name empty string:

Escape Sequences

A sequence that starts with a \ in a string is called an escape sequence. It allows us to include special characters in our strings.

Common escape sequences are:

You saw one escape sequence previously: \n is used to denote a new line.

Each escape sequence is considered one character.

Basic Operations with Strings

The following are some of the basic methods for string manipulation. Have a look at their codes.

Length of a String

The length of a string can be found using a simple method nchar(). Let’s find the length of the string “learning is fun”.

Empty spaces or tabs, i.e. \t, are also considered characters and are added in the total length of the string.

Why Do We Not Use length() Here?

The keyword length() gives the length of R objects for which this method has been defined. It returns the number of elements in the object, so for a single string it will return $1$.

Concatenating Two Strings

Two strings can be concatenated using paste().

By default, paste() inserts a single space between pairs of strings.

However, this default setting can be overridden using the sep argument in paste().

For example, we can set a . or an empty string "" as a separator.

Duplicating Strings

We can duplicate the same string multiple times using the keywords replicate() or rep().

Syntax for replicate()

replicate(<numberOfTimes>, <stringToReplicate>)

Syntax for rep()

rep(<stringToReplicate>, <numberOfTimes>)

The parameter numberOfTimes specifies how many times to repeat the parameter stringToReplicate.

Both rep and replicate perform the same task. However, the order of the arguments is the opposite.