dplyr Select

Introduction

The select() function in dplyr is used to select columns from a data frame. It offers powerful column selection capabilities.

Basic Selection

library(dplyr)

df <- tibble(
  id = 1:5,
  name = c("Alice", "Bob", "Charlie", "David", "Eve"),
  age = c(25, 30, 35, 40, 45),
  score = c(85, 90, 78, 92, 88)
)

# Select single column
select(df, name)

# Select multiple columns
select(df, name, age)

# Select range of columns
select(df, name:age)

Selection Helpers

df <- tibble(
  id = 1:5,
  name = c("Alice", "Bob", "Charlie", "David", "Eve"),
  age = c(25, 30, 35, 40, 45),
  score1 = 85,
  score2 = 90,
  score3 = 78
)

# By pattern
select(df, starts_with("score"))

# Ends with
select(df, ends_with("e"))

# Contains
select(df, contains("a"))

# Matches regex
select(df, matches("^s"))

Advanced Selection

# Everything
select(df, everything())

# Select by column number
select(df, 1:3)

# Exclude columns
select(df, -id)

# Using where
select(df, where(is.numeric))

Rename with Select

# Rename
select(df, new_name = old_name)

# Rename and keep
select(df, new_name = old_name, everything())

Summary

select() provides flexible ways to choose columns in R. Master these helpers for efficient data manipulation.