[R] 221011_예시 복습

### 2주차 예시 복습

## 예시 1)

# 문제

d <- c(100:200)

# coding here #

d[50]

d[seq(1,110,10)]

d[c(1:20)]

## 예시 2)

# 문제

d <- c(100:200)

# coding here #

length(d)

mean(d)

sum(d<110)

sum(d[d<110])

## 예시 3)

# 문제

x <- c(1:20)

# coding here #

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

y

sort(y, decreasing = T)

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

## 예시 4)

# 문제

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

# coding here #

a <-  sort(a)

a

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

a

## 예시 5)

# 문제

ages <- c(58,20,85)

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

x <- list(ages,names)

# coding here #

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

x

## 예시 6)

# 문제

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

gender_fac <- factor(gender)

# coding here #

gender_fac[16] <- 'male'

summary(gender_fac)

### 3주차 예시 복습

## 예시 1)

# coding here #

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

d

## 예시 2)

# 문제

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

# coding here #

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

d_t

## 예시 3)

# 문제

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

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

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

# coding here #

m1 <- cbind(b1,b2,b3)

m1

## 예시 4)

# 문제

# coding here #

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

rich_state.x77

## 예시 5)

# 문제

x <- c(1,2,3)

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

z <- c(TRUE, FALSE, TRUE)

# coding here #

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

df

## 예시 6)

# 문제

class(airquality)

# coding here #

airquality_m <- as.matrix(airquality)

airquality_m

## 예시 7)

# 문제

# coding here #

nrow(subset(airquality, Ozone>120))

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

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

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

## 예시 8)

# 문제

# coding here #

airquality['Wind'] # 데이터 프레임

airquality[,'Wind'] # 벡터

airquality$Wind # 벡터

### 5주차 예시 복습

## 예시 1)

# 문제

# coding here #

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

air_6

write.table(air_6, file='air_6.txt', row.names=F)

## 예시 2)

# 문제

# coding here #

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

swiss_F

write.csv(swiss_F, file='swiss_F.csv')

## 예시 3)

# 문제

# coding here #

sw_F <- readLines('swiss_F.csv')

sw_F

## 예시 4)

# 문제

# coding here #

swd_F <- read.csv('swiss_F.csv', header=T)

swd_F

## 예시 5)

# 문제

# coding here #

colSums(swiss['Education'])

sum(swiss$Education)

colMeans(swiss['Examination'])

mean(swiss$Examination)

sort(swiss$Agriculture)

## 예시 6)

# 문제 생략

## 예시 7)

# 문제

# coding here #

swd_F1 <- subset(swiss, Infant.Mortality>20)

swd_F1

View(swd_F1)