Summary  
This chapter covers accessing named columns in a data frame using square bracket indexing and the dollar-sign shorthand.

General domain of usage  
Data analysis

Data frames always have named columns, and you can use these names to extract specific columns. There are two main approaches.

## Using Square Brackets
You can specify the column name inside square brackets.

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

# Extracting the name with square brackets
test[, "name"]

## Using the Dollar Sign
Data frames also support a shorthand operator, `$`, which allows you to access a column by name without quotes.

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

# Extracting the name with dollar sign
test$name

Gain a solid understanding of R, one of the most widely used languages for data analysis. Explore fundamental data types and one-dimensional values, then advance to multi-dimensional structures, including matrices, data frames, and lists. Build the skills needed to apply R effectively in statistical analysis and data-driven decision-making.

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Accessing Columns in Data Frames

Using Square Brackets

Example

Using the Dollar Sign

Example

Solution

Awesome!

Accessing Columns in Data Frames

Using Square Brackets

Example

Using the Dollar Sign

Example

Solution