Hello guys, what’s up? I have found that many of you are searching about $ symbol in r. It’s quite easy. Let’s start—

In R programming language, there are 4 forms of the extract operator. Those are [, [[, $, and @. 

Here I am not discussing about the entire operator. I just clarify you what is $ symbol in r with proper example.
As earlier what I have told, $ is used to extract content from a single object. Then means it is used to refer to an element in a list or a column in a data frame.

We often want to select an entire column, namely one specific variable from a data frame. If we want to select all elements of the variable diameter, we can just write this—

nameOf_dataframe$nameOf_colomn
Or you can write like below—
nameOf_dataframe[,positionOf_colomn]  nameOf_dataframe[,”nameOf_colomn”]


Theoretical Explanation:

hi$John

Then it returns all of the values in the column labeled john. Assuming that the numbers are the actual column numbers, we can get the same result by calling:

hi[, 1]

It returns all values in column index position ‘1’.

Mylist = list (x=1, y=42)
Mylist$y 

After execution of it, it will print 42

x <- list(a=1, b=2, c=3)
x$b
# [1] 2

So, guys, that’s all about $ symbol in r. Later we will discuss another topic of r programming language. Till then, take care. Happy Coding