3 Manipulating Columns

Please copy the following code and paste them into a script in the RStudio. We will walk through them with the visual explanations from the dplyr cheat sheet.

Input

# Sample code from the dplyr cheat sheet
## 3.1 Select columns
pull(mtcars, wt)
select(mtcars, mpg, wt)

## 3.2 Arrange columns
relocate(mtcars, mpg, cyl, .after = last_col())

## 3.3 Add columns
mutate(mtcars, gpm = 1 / mpg)
transmute(mtcars, gpm = 1 / mpg)
### A showcase for bind_cols
x <- data.frame(
  A = c('a', 'b', 'c'), 
  B = c('t', 'u', 'v'),
  C = c(1, 2, 3))
x
y <- data.frame(
  E = c('a', 'b', 'd'), 
  F = c('t', 'u', 'w'),
  G = c(3, 2, 1))
y
bind_cols(x, y) # you have to make sure the binding is meaningful by yourself

## 3.4 Rename columns
rename(cars, distance = dist)

3.1 Select Columns

3.2 Arrange Columns

3.3 Add Columns

3.4 Rename Columns

Practice 3

iris is a data frame with 150 cases (rows) and 5 variables (columns) named Sepal.Length, Sepal.Width, Petal.Length, Petal.Width, and Species. Make a new data frame which contains only Species and the ratio of Petal.Width and Petal.Length.

This page is meant to introduce functions that help manipulate columns.
A pause here for questions.