ABSTRACT
R has powerful tools for computing not only on values, but also on the actions that lead to those values. If you’re coming from another programming language, they are one of the most surprising features of R. Consider the following simple snippet of code that plots a sine curve:
x <- seq(0, 2 * pi, length = 100)
sinx <- sin(x)
plot(x, sinx, type = "l")
Look at the labels on the axes. How did R know that the variable on the x axis is called x and the variable on the y axis is called sinx? In most programming languages, you can only access the values of a function’s the used to compute
ways: to what is known as non-standard evaluation, or NSE for short. NSE is particularly useful for functions when doing interactive data analysis because it can dramatically reduce the amount of typing.
