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Columns Accessors
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Course Content

R Introduction: Part II

Columns AccessorsColumns Accessors

Since data frames have names on their columns, you should be able to extract necessary data using them.

There are several ways in R to refer to a particular column using naming. One of them is the same as in vectors and matrices: column name within square brackets (for example, data[, "col_name"]). The second way is unique for data frames - using the dollar $ sign. The syntax is data$col_name (yes, without quotation marks). For example, you can extract the column "Age" from the data frame created in the last chapter.


Let's work with the mtcars dataset. Your tasks are:

  1. Extract the cyl column values using square brackets.
  2. Extract the disp column values using the dollar $ sign.

Everything was clear?

Section 2. Chapter 3
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