Vectors

Vectors are used to store single or multiple values of similar data types in a variable and are considered to be one-dimensional arrays. That means that the x variable we just defined is a vector. If we want to create a vector with multiple numeric values, we assign as before with one additional rule: we put all the values inside c() and separate all the values with , except the last value. Let's look at an example:

val = c(1, 2, 3, 4, 5, 6)

What happens if we mix different data types such as both numerics and characters? It works! (A variable's name is arbitrarily named as val, but you can name your variable anything that you feel appropriate, anything!) Except in some cases, such as variable names, shouldn't start with any special character:

x = c(1, 2.0, 3.0, 4, 5, "Hello", "OK")

What we have just learned about storing data of the same types doesn't seem to be true then, right? Well, not exactly. What R does behind the scenes is that it tries to convert all the values mentioned for the x variable to the same type. As it can't convert Hello and OK to numeric types, for conformity it converts all the numeric values 1, 2.0, 3.0, 4, and 5 to character values: that is, "1", "2.0", "3.0", "4", and "5", and adds two more values, "Hello" and "OK", and assigns all these character values to x. We can check the class (data type) of a variable in R with class(variable_name), and let's confirm that x is indeed a character variable:

class(x)

We will see that the R window will show the following output:

[1] "character"

We can also label vectors or give names to different values according to our need. Suppose we want to assign temperature values recorded at different times to a variable with a recorded time as a label. We can do so using this code:

temperature = c(morning = 20, before_noon = 23, after_noon = 25, evening = 22, night =  18)