生信入门 第四天

This is my day 4 homework of BIC by 生信星球.

The content for today is the introduction of R and R studio.

1. Installation of R project and R studio

Watch the tutorial video on bilibli: https://www.bilibili.com/video/BV1J44y1R7ci/?share_source=copy_web&vd_source=ba670d5a7ca081b044384f15866b88ef

All done.

an interesting exaple of r application:

plot(rnorm(50))  
#plot() is a default scatterplot function in r. 
#rnorm() generates n random numbers from a normal distribution with the mean and sd you specify. 

another example:

boxplot(iris$Sepal.Length~iris$Species,col = c("lightblue","lightyellow","lightpink"))

2. Change the appearence

Tools -> Appearence->Global options

3. Basic opereation of R

3.1 Managing working directory

Read a previous paper for this point.

https://mp.weixin.qq.com/s/G-LXN9P2HVLv9v0cvyFJMA

setwd() #设置工作目录
getwd() #查看工作目录

3.2 Show the list of files

> dir()             
> list.files()

3.3 Mathematic calculation

add, minus, multiple, divide, and log (skip).

3.4 create variable

syntax: <-

x <- 1+2

my question is what is the difference between <- and =?

3.5 delete variable

example:

a <- 5 #赋值 a
b <- 18 #赋值b
c <- 26 #赋值c
u <- a + b #赋值u
rm(b)  #删除 b
rm(u,c)  #删除 u，c
rm(list = ls()) #清空所有变量

tips： tab key for filling in the rest of command or file name as far as it can automatically.

3.6 check the history of commands

history()

3.7 clean the console

fast keys:

ctrl + l