[R] 221016_복습

### 2주차

## 1)

d <- c(100:200)

d[50]

d[seq(1,110,10)]

d[c(1:20)]

## 2)

length(d)

mean(d)

sum(d<110)

sum(d[d<110])

## 3)

x <- c(1:20)

y <- x[seq(3,20,3)]

y

sort(y, decreasing = T)

mean(x[-c(2:10)])

## 4)

a <- c(1,6,3,8)

a <- sort(a)

a

names(a) <- c('one','three','six','eight')

a

## 5)

ages <-  c(58,20,85)

names <- c('Tony','Ahn','Nick')

x <- list(ages,names)

names(x) <- c('numbers','names')

x

## 6)

gender <- c(rep('male',5),rep('female','10'))

gender_fac <- factor(gender)

gender_fac[16] <- 'male'

summary(gender_fac)

### 3주차 복습

## 1)

d <- matrix(seq(5,60,5),nrow=3,ncol=4, byrow=F)

d

## 2)

d <- matrix(seq(5,60,5), nrow = 3, ncol = 4, T)

d

## 3)

b1 <- c(4,5,7,2)

b2 <- c(19,15,12,17)

b3 <- c(20,24,28,23)

m1 <- cbind(b1,b2,b3)

m1

m2 <- cbind(b1,m1,b2)

m2

## 4)

rich <- subset(as.data.frame(state.x77), Income>=5000)

rich

## 5)

x <- c(1,2,3)

y <- c('white','blue','yellow')

z <- c(T, F, T)

df <- data.frame(x,y,z)

df

## 6)

airquality_m <- as.matrix(airquality)

class(airquality_m)

## 7)

nrow(subset(airquality, Ozone>120))

subset(airquality, Temp==max(airquality$Temp))

subset(airquality, Temp==max(airquality[,'Temp']))

subset(airquality, Temp==max(airquality['Temp']))

## 8)

airquality[,'Wind']

airquality$Wind

### 5주차 복습

## 1)

air_6 <- subset(airquality, Month==6)

air_6

write.table(air_6, file='air_6_221016.txt', row.names =F, col.names =T)

## 2)

swiss_F <- subset(swiss, Fertility>=90)

swiss_F

write.csv(swiss_F, file='swiss_F_221016.csv', row.names = T)

## 3)

sw_F <- readLines('swiss_F_221016.csv')

sw_F

## 4)

swd_F <- read.csv('swiss_F_221016.csv')

swd_F

## 5)

sum(swiss$Education)

colSums(swiss['Education'])

mean(swiss$Examination)

colMeans(swiss['Examination'])

sort(swiss$Agriculture)

## 6)

rank <- sort(swiss$Education)

rank

## 7)

swd_F <- subset(swiss, Infant.Mortality>20)

nrow(swd_F)

View(swd_F)

### 6주차 복습

## 1)

num_col <- nrow(iris)

b = c()

for (i in 1:num_col){

  if (iris$Petal.Length[i]<=1.6){

    b[i] <- 'L'

  } else if (iris$Petal.Length[i]>=5.1){

    b[i] <- 'H'

  } else{b[i] <- 'M'}

}

b

## 2)

for (i in 1:24){

  if (24%%i==0){

    print(i)

  }

}

## 3)

num <- 0

sum <- 0

for (i in 1:100){

  if (i%%3==0){

    num <- num+1

    sum <- sum+i

  }

}

cat(num,sum)

## 4)

i <- 1

k <- 1

while(i<6){

  k <- k*i

  i <- i+1  

}

print(k)

## 5)

apply(iris[,1:4],1,sum)

apply(iris[,1:4],2,max)

apply(iris[,1:4],2,min)

iris

colSums(swiss[,-3])

rowSums(iris[,-5])

View(swiss)

ame(iris$Petal.Length, new.Label)

new_data_frame