Subsetting a vector in R is the process of extracting elements from a vector based on a set of criteria. The [ operator is used to subset vectors in R.
The [ operator can be used to extract single elements, multiple elements, or ranges of elements from a vector. For example, the following code would extract the first element of the vector x:
x <- c("a", "b", "c", "d", "e")
x[1]
The following code would extract the first two elements of the vector x:
x[1:2]
The following code would extract the elements of the vector x that are greater than "a":
x[x > "a"]
The [ operator can also be used to extract elements of a vector by name. For example, the following code would extract the element named "a" from the vector x:
x["a"]
Subsetting vectors is a powerful tool that can be used to extract the data you need from a vector.
Examples of subsetting vectors in R:
To extract the last element of a vector, you can use the following code:
x[length(x)]
To extract every other element of a vector, you can use the following code:
x[seq(2, length(x), by = 2)]
To extract the elements of a vector that are even, you can use the following code:
x[x %% 2 == 0]
To extract the elements of a vector that are greater than 10 and less than 20, you can use the following code:
x[x > 10 & x < 20]
