creat a matrix

q class (q)

is.character(q)

Hubei <- c (47, 19, 50, 46, 9, 4) Henan <- c (10, 3, 0, 16, 3, 0) Guangxi <- c (40, 5, 10, 8, 0, 6) Shandong <- c (2, 0, 7, 4, 0, 0) Hebei <- c (2, 2, 0, 0, 2, 0) Tianbao <- c (47, 10, 40, 2, 2) Yangjiaosu <- c (19, 3, 5, 0, 2) Niujiaosu <- c (50, 0, 10, 7, 0) Bailan <- c (46, 16, 8, 4, 0) Huangjing <- c (9, 3, 0, 0, 2) Xiaomaisu <- c (4, 0, 6, 0, 0) my_matrix <- cbind(Hubei, Henan, Guangxi, Shandong, Hebei) my_matrix

rownames(my_matrix)<- c(“Tianbao”, “Yangjiaosu”, “Niujiaosu”, “Bailan”, “Huangjing”, “Xiaomaisu”) my_matrix

A = 2 A is.numeric (A) class (A) as.character (A) class (A) class (“2”) B = as.character (A) class (B) B == A B != A is.na is.na (A) myvector = seq(2,10,by = 2) myvector myvector [c(1,5)] substr (myvector,1,5) myvector = seq(2, 10, by = 2) c(myvector > 5) sort(myvector,decreasing = TRUE) order (myvector) order (myvector, decreasing = TRUE)

myvector = seq(2, 10, by = 2) myvector

myvector[myvector > 5]

myvector [5]

sort(myvector,decreasing=TRUE) order(myvector)

myvector[order(myvector)]

aa = rep (LETTERS [1:2], times =2) aa class (aa) bb = as.factor (aa) bb is.factor (bb) is.factor (aa) as.factor (aa) is.factor(aa) levels (bb) levels (bb) = c (“B”, “A”) bb

bb = factor (bb, levels = c(“B”, “A”)) bb col1 = c(5,6,7,8,9) col2 = c (2,4,5,9,8) mymatrix = cbind (col1, col2) mymatrix rownames (mymatrix) <- c (“row1”, “row2”, “row3”, “row4”, “row5”) mymatrix colnames (mymatrix) <- c (“ha1”, “ha2”) mymatrix t (mymatrix) ?matrix matrix(data = c(1,2,3,4,5,6), nrow = 2, ncol = 3, byrow = FALSE, dimnames = list (c(“r1”, “r2”), c(“c1”, “c2”, “c3”))) ?list

hh = matrix(data = c(1,2,3,4,5,6), nrow = 2, ncol = 3, byrow = TRUE, dimnames = list (c(“r1”, “r2”), c(“c1”, “c2”, “c3”))) hh t(hh)

mymatrix mymatrix[mymatrix [ ,“ha2?”] > 4, ]

x = c(1:4) x

ha <- matrix (data = c(1:9), nrow = 3, by row = TRUE,dimnames = list (c(“r1”, “r2”, “r3”), c (“aa”, “bb”, “cc”)) )

aa = c (1:3) bb = c (4:6) cc = c (7:9) matrix <- cbind (aa, bb, cc) matrix

rownames (matrix) <- c (“r1”, “r2”, “r3”) matrix

dd <- matrix [,3] - matrix [,2] dd newmatrix <- cbind (matrix, dd) newmatrix

h1 = matrix (data = 1:9, 3,3, dimnames = list (c(“r1”, “r2”, “r3”), c(“c1”, “c2”, “c3”))) h1

yield <- c(1:4) yield

cultivar<-c(LETTERS[1:4]) cultivar

mydata <- data.frame (yield, cultivar) mydata

rownames (mydata) <- c(“h1”, “h2”, “h3”, “h4”) mydata

mydata$color = c(“green”, “blue”, “red”, “pink”) mydata

color <- c(“green”, “blue”, “red1”, “pink”) color mydata1 <- cbind (mydata, color) mydata1

exper1 <- c(4:7) pre1

exper2<-c(letters[1:4]) expe2

myfield <- data.frame (exper1, exper2, color) myfield

mergeall <- merge(mydata1, myfield, by = “color”) mergeall

mydata [-1,]

myvector <- c(1:3) myvector

d1 = matrix(LETTERS[1:6], nrow = 3, byrow = T, dimnames = list(c(“row1”, “row2”, “row3”), c(“col1”, “col2”))) d1 d

rownames(d) <- c(“row1”, “row2”, “row3”) colnames (d) <- c(“col1”, “col2”) d class(d)

mymatrix <- d mymatrix

mydataframe <- data.frame(myvector, mymatrix) mydataframe

mylist = list(myvector, mymatrix, mydataframe) mylist mylist [[3]] mylist$[[mydataframe]]

names([[1]])= “myvector”

data (“datasets”)

head(mtcars,3)

?PlantGrowth

data(“npk”) npk

nrow(npk) ncol(npk)

head(npk,24) class(npk)

npk[c(22:24), ]

str(npk) names(npk) factor(npk)

class(yield)

factor()

!NA

Fruit_1 = read.csv (“Fruit.csv”) head(“Fruit_1.csv”)

read.csv(“Fruit.xsl”)

library(readx1)

path<- readx1_example(“Fruit.xls”)

setwd(“d:/myproject”)

dim(“Fruit.xls”)

print(“Fruit.xls”)

head(cars,3) dim(cars) plot(cars)

plot(cars\(speed~ cars\)dist)

qqnorm(cars\(speed) qqline(cars\)speed)

head(mtcars[1:2]) boxplot(mtcars\(mpg, mtcars\)cyl)

Fruit = read.csv (“Fruit.xls”)

head(iris[1:4]) pairs(iris[1:4])

table(iris\(Sepal.Length) barplot(iris\)Sepal.Length)

```