CODEWITHSUNDEEP
rcharacterstring
Zander
Zander

Reputation: 1018

Differences between character() and "" in R

Just realize the output is different:

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

However, nothing odd has happened. And I am not clear about these differences, and want to keep this problem(if any) clear in mind. So, thank you for helping.

Upvotes: 7

Views: 1139

Answers (3)

Spacedman
Spacedman

Reputation: 94202

You are confusing the length (number of elements) of a vector with the number of characters in a 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 how many letters in each element of x, so it returns an integer vector of two zeroes. nchar(y) is then an integer vector of one zero.

So the last one, nchar(z) returns an integer(0), which is an integer vector of no zeroes. It has length of zero. It has no elements, but if it did have elements, they would be integers.

character(0) is an empty vector of character-type objects. Compare:

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

Upvotes: 5

Randy Lai
Randy Lai

Reputation: 3174

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

Upvotes: 3

bartektartanus
bartektartanus

Reputation: 16080

character(0) is vector of character type with ZERO elements. But "" is character type vector with one element, which is equal to empty string.

Upvotes: 6

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