basic_R_operations.md

Lab4_Question 7

Peng Zhang 2022-10-01

Introduction

This report is to demonstrate how to create a dataframe in R and do a few simple operations.

Create a new dataframe

We can create a toy dataframe from the below code:

df <- data.frame(name = c('John', 'Ty', 'Jim'),
                 age = c(21, 30, 45),
                 title = c('Estimator', 'Engineer', 'Manager'))
df

##   name age     title
## 1 John  21 Estimator
## 2   Ty  30  Engineer
## 3  Jim  45   Manager

Operations on dataframe

We can select a particular column and output the specified column only.

# load necessary library
library(tidyverse)

## ── Attaching packages ─────────────────────────────────────── tidyverse 1.3.2 ──
## ✔ ggplot2 3.3.6     ✔ purrr   0.3.4
## ✔ tibble  3.1.8     ✔ dplyr   1.0.9
## ✔ tidyr   1.2.0     ✔ stringr 1.4.1
## ✔ readr   2.1.2     ✔ forcats 0.5.2
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## ✖ dplyr::filter() masks stats::filter()
## ✖ dplyr::lag()    masks stats::lag()

df_1 <- df |> select(title)
df_1

##       title
## 1 Estimator
## 2  Engineer
## 3   Manager

We can filter the dataframe based on a certain condition. In the following example, it will only output people with their age over 30.

df_2 <- df |> filter(age >30)
df_2

##   name age   title
## 1  Jim  45 Manager