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Columns 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.


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# Data
name <- c("Alex", "Julia", "Finn")
age <- c(24, 43, 32)
gender <- c("M", "F", "M")
# Creating a data frame
test <- data.frame(name, age, gender)

# Extracting the name column using two ways
test[,"name"]
test$name

Opgave

Swipe to start coding

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

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

Løsning

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Sektion 2. Kapitel 3

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Columns Accessors

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


              12345678910
            
# Data
name <- c("Alex", "Julia", "Finn")
age <- c(24, 43, 32)
gender <- c("M", "F", "M")
# Creating a data frame
test <- data.frame(name, age, gender)

# Extracting the name column using two ways
test[,"name"]
test$name

Opgave

Swipe to start coding

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

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

Løsning

Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder

Var alt klart?

Tak for dine kommentarer!

Sektion 2. Kapitel 3

Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder