R包的安装和使用(以dplyr为例)
1.安装和加载R包
(1)镜像设置
代码语言:R复制options("repos" = c(CRAN="https://mirrors.tuna.tsinghua.edu.cn/CRAN/")) #对应清华源
options(BioC_mirror="https://mirrors.ustc.edu.cn/bioc/") #对应中科大源
(2)安装
代码语言:R复制install.packages("包")#安装包存在于CRAN网站用这个命令安装
BioManager::install("包")#Biocductor网站的安装包
(3)加载
library和require两个函数均可以加载,需要先安装后加载options("repos" = c(CRAN="https://mirrors.tuna.tsinghua.edu.cn/CRAN/")) options(BioC_mirror="https://mirrors.ustc.edu.cn/bioc/") install.packages("dplyr") library(dplyr)2.dplyr包的使用(五个基础函数)
(1)mutate()#新增列
代码语言:R复制mutate(test, new = Sepal.Length * Sepal.Width)
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species new
## 1 5.1 3.5 1.4 0.2 setosa 17.85
## 2 4.9 3.0 1.4 0.2 setosa 14.70
## 3 7.0 3.2 4.7 1.4 versicolor 22.40
## 4 6.4 3.2 4.5 1.5 versicolor 20.48
## 5 6.3 3.3 6.0 2.5 virginica 20.79
## 6 5.8 2.7 5.1 1.9 virginica 15.66
(2)select()#按列筛选
- 按列号筛选select(test,1) ## Sepal.Length ## 1 5.1 ## 2 4.9 ## 51 7.0 ## 52 6.4 ## 101 6.3 ## 102 5.8 select(test,c(1,5)) ## Sepal.Length Species ## 1 5.1 setosa ## 2 4.9 setosa ## 51 7.0 versicolor ## 52 6.4 versicolor ## 101 6.3 virginica ## 102 5.8 virginica select(test,Sepal.Length) ## Sepal.Length ## 1 5.1 ## 2 4.9 ## 51 7.0 ## 52 6.4 ## 101 6.3 ## 102 5.8select(test, Petal.Length, Petal.Width) ## Petal.Length Petal.Width ## 1 1.4 0.2 ## 2 1.4 0.2 ## 51 4.7 1.4 ## 52 4.5 1.5 ## 101 6.0 2.5 ## 102 5.1 1.9 vars <- c("Petal.Length", "Petal.Width") select(test, one_of(vars)) ## Petal.Length Petal.Width ## 1 1.4 0.2 ## 2 1.4 0.2 ## 51 4.7 1.4 ## 52 4.5 1.5 ## 101 6.0 2.5 ## 102 5.1 1.9(3)filter()筛选行filter(test, Species == "setosa") ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## 1 5.1 3.5 1.4 0.2 setosa ## 2 4.9 3.0 1.4 0.2 setosa filter(test, Species == "setosa"&Sepal.Length > 5 ) ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## 1 5.1 3.5 1.4 0.2 setosa filter(test, Species %in% c("setosa","versicolor")) ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## 1 5.1 3.5 1.4 0.2 setosa ## 2 4.9 3.0 1.4 0.2 setosa ## 3 7.0 3.2 4.7 1.4 versicolor ## 4 6.4 3.2 4.5 1.5 versicolor(4)arrange(),按某1列或某几列对整个表格进行排序arrange(test, Sepal.Length)#默认从小到大排序 ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## 1 4.9 3.0 1.4 0.2 setosa ## 2 5.1 3.5 1.4 0.2 setosa ## 3 5.8 2.7 5.1 1.9 virginica ## 4 6.3 3.3 6.0 2.5 virginica ## 5 6.4 3.2 4.5 1.5 versicolor ## 6 7.0 3.2 4.7 1.4 versicolor arrange(test, desc(Sepal.Length))#用desc从大到小 ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## 1 7.0 3.2 4.7 1.4 versicolor ## 2 6.4 3.2 4.5 1.5 versicolor ## 3 6.3 3.3 6.0 2.5 virginica ## 4 5.8 2.7 5.1 1.9 virginica ## 5 5.1 3.5 1.4 0.2 setosa ## 6 4.9 3.0 1.4 0.2 setosa(5)summarise():汇总summarise(test, mean(Sepal.Length), sd(Sepal.Length))# 计算Sepal.Length的平均值和标准差 ## mean(Sepal.Length) sd(Sepal.Length) ## 1 5.916667 0.8084965 # 先按照Species分组,计算每组Sepal.Length的平均值和标准差 group_by(test, Species) ## # A tibble: 6 x 5 ## # Groups: Species [3] ## Sepal.Length Sepal.Width Petal.Length Petal.Width Species ## * <dbl> <dbl> <dbl> <dbl> <fct> ## 1 5.1 3.5 1.4 0.2 setosa ## 2 4.9 3 1.4 0.2 setosa ## 3 7 3.2 4.7 1.4 versicolor ## 4 6.4 3.2 4.5 1.5 versicolor ## 5 6.3 3.3 6 2.5 virginica ## 6 5.8 2.7 5.1 1.9 virginica summarise(group_by(test, Species),mean(Sepal.Length), sd(Sepal.Length)) ## # A tibble: 3 x 3 ## Species `mean(Sepal.Length)` `sd(Sepal.Length)` ## ## 1 setosa 5 0.141 ## 2 versicolor 6.7 0.424 ## 3 virginica 6.05 0.354dplyr两个实用技能(1)管道操作 %>% (快捷键:ctr shift M)test %>% group_by(Species) %>% summarise(mean(Sepal.Length), sd(Sepal.Length)) ## # A tibble: 3 x 3 ## Species `mean(Sepal.Length)` `sd(Sepal.Length)` ## ## 1 setosa 5 0.141 ## 2 versicolor 6.7 0.424 ## 3 virginica 6.05 0.354%>%向右依次执行命令
- 按列名筛选
(2)count统计某列的unique值
代码语言:R复制count(test,Species)
## # A tibble: 3 x 2
## Species n
##
## 1 setosa 2
## 2 versicolor 2
## 3 virginica 2
dplyr处理关系数据
代码语言:R复制test1 <- data.frame(x = c('b','e','f','x'),
z = c("A","B","C",'D'))
test1
## x z
## 1 b A
## 2 e B
## 3 f C
## 4 x D
test2 <- data.frame(x = c('a','b','c','d','e','f'),
y = c(1,2,3,4,5,6))
test2
## x y
## 1 a 1
## 2 b 2
## 3 c 3
## 4 d 4
## 5 e 5
## 6 f 6
(1)内连inner_join,取交集
代码语言:R复制inner_join(test1, test2, by = "x")
## x z y
## 1 b A 2
## 2 e B 5
## 3 f C 6
(2)左连left_join
代码语言:R复制left_join(test1, test2, by = 'x')
## x z y
## 1 b A 2
## 2 e B 5
## 3 f C 6
## 4 x D NA
left_join(test2, test1, by = 'x')
## x y z
## 1 a 1 NA
## 2 b 2 A
## 3 c 3 NA
## 4 d 4 NA
## 5 e 5 B
## 6 f 6 C
(3)全连full_join
代码语言:R复制full_join( test1, test2, by = 'x')
## x z y
## 1 b A 2
## 2 e B 5
## 3 f C 6
## 4 x D NA
## 5 a NA 1
## 6 c NA 3
## 7 d NA 4
(4)半连接:返回能够与y表匹配的x表所有记录semi_join
代码语言:R复制semi_join(x = test1, y = test2, by = 'x')
## x z
## 1 b A
## 2 e B
## 3 f C
(5)反连接:返回无法与y表的所记录anti_join
代码语言:R复制anti_join(x = test2, y = test1, by = 'x')
## x y
## 1 a 1
## 2 c 3
## 3 d 4
(6)简单合并
代码语言:R复制在相当于base包里的cbind()函数和rbind()函数;注意,bind_rows()函数需要两个表格列数相同,而bind_cols()函数则需要两个数据框有相同的行数
test1 <- data.frame(x = c(1,2,3,4), y = c(10,20,30,40))
test1
## x y
## 1 1 10
## 2 2 20
## 3 3 30
## 4 4 40
test2 <- data.frame(x = c(5,6), y = c(50,60))
test2
## x y
## 1 5 50
## 2 6 60
test3 <- data.frame(z = c(100,200,300,400))
test3
## z
## 1 100
## 2 200
## 3 300
## 4 400
bind_rows(test1, test2)
## x y
## 1 1 10
## 2 2 20
## 3 3 30
## 4 4 40
## 5 5 50
## 6 6 60
bind_cols(test1, test3)
## x y z
## 1 1 10 100
## 2 2 20 200
## 3 3 30 300
## 4 4 40 400