Differences between the character () and "" in R

Question

Just realize that the output is different:

> y="" > y [1] "" > y=character() > y character(0) 

However, nothing strange happened. And I do not quite understand these differences and I want this problem (if any) to be understood. So thanks for the help.

Answer 1

You confuse the length (number of elements) of the vector with the number of characters in the string:

Consider these three things:

 > x=c("","") > y="" > z=character() 

Their length is the number of elements in the vector:

 > length(x) [1] 2 > length(y) [1] 1 > length(z) [1] 0 

To get the number of characters, use nchar :

 > nchar(x) [1] 0 0 > nchar(y) [1] 0 > nchar(z) integer(0) 

Note that nchar(x) shows the number of letters in each element of x , so it returns an integer vector of two zeros. nchar(y) is an integer vector of one zero.

So the last one, nchar(z) returns integer(0) , which is an integer vector without zeros. It has a length of 0. It has no elements, but if it had elements, they would be integers.

character(0) - an empty vector of character type objects. For comparison:

 > character(0) character(0) > character(1) [1] "" > character(2) [1] "" "" > character(12) [1] "" "" "" "" "" "" "" "" "" "" "" "" 

Answer 2

character(0) is a character type vector with ZERO elements. But "" is a character-type vector with one element that is equal to an empty string.

Answer 3

If y="" , then length(y) - 1 . On the other hand, if y=character() , then length(y) is 0