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R Variables


Creating Variables in R

Variables are containers for storing data values.

R does not have a command for declaring a variable. A variable is created the moment you first assign a value to it. To assign a value to a variable, use the <- sign. To output (or print) the variable value, just type the variable name:

Example

name <- "John"
age <- 40

name   # output "John"
age    # output 40
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From the example above, name and age are variables, while "John" and 40 are values.

In other programming language, it is common to use = as an assignment operator. In R, we can use both = and <- as assignment operators.

However, <- is preferred in most cases because the = operator can be forbidden in some context in R.


Print / Output Variables

Compared to many other programming languages, you do not have to use a function to print/output variables in R. You can just type the name of the variable:

Example

name <- "John Doe"

name # auto-print the value of the name variable
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However, R does have a print() function available if you want to use it. This might be useful if you are familiar with other programming languages, such as Python, which often use a print() function to output variables.

Example

name <- "John Doe"

print(name) # print the value of the name variable
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And there are times you must use the print() function to output code, for example when working with for loops (which you will learn more about in a later chapter):

Example

for (x in 1:10) {
  print(x)
}
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Conclusion: It is up to your if you want to use the print() function or not to output code. However, when your code is inside an R expression (for example inside curly braces {} like in the example above), use the print() function if you want to output the result.