df_csv_exam<-read("c:/easy_0405/csv.exam.csv")
df_csv_exam<-read.csv("c:/easy_0405/csv.exam.csv")
df_csv_exam<-read.csv("C:\Users\Admin\Documents\easy_0405/csv.exam.csv")
df_csv_exam<-read.csv("C:\Admin\Documents\easy_0405/csv.exam.csv")
df_csv_exam<-read.csv("C:\Documents\easy_0405/csv.exam.csv")
df_csv_exam<-read.csv("C:/easy_0405/csv_exam.csv")
df_csv_exam<-read.csv("C:/Users/Admin/Documents/easy_0405/csv_exam.csv")
df_csv_exam
df_csv_exam<-read.csv("csv_exam.csv")
df_csv_exam
df_csv_exam<-read.csv("C:/Users/Admin/Documents/easy_0405/csv_exam.csv")
df_csv_exam
df_csv_exam<-read.csv("C:/Users/Admin/Documents/easy_0405/csv_exam.csv", stringsAsFactors = F)
df_midterm <- data.frame(english=c(90,80,60,70),
math=c(50,60,70,100),
class=c(1,1,2,2))
df_midterm
write.csv(df_midterm, file="df_midterm.csv")
df_midterm
head(exam)
exam<-read.csv("csv_examcsv")
exam<-read.csv("csv_exam.csv")
head(exam)
## 데이터프레임 이름 뒤 쉼표쓰고 숫자 입력 -> 입력한 행까지 데이터 출력
head(exam,10)
## 2. 데이터의 뒷부분 출력
tail(exam)
View(exam)
dim(exam)
str(exam)
summary(exam$class)
summary(exam$english)
install.packages("ggplot2")
library(ggplot2)
mpg<-as.data.frame(ggplot::mpg)
mpg<-as.data.frame(ggplot2::mpg)
head(mpg)
View(mpg)
summary(mpg)
df_raw<-data.frame(var1=c(1,2,1),
var2=c(2,3,2))
df_raw
install.packages("dplyr")
library(dplyr)
df_new<-df_raw
df_new
df_new<-rename(df_new,v2=var2)
df_new
#혼자 해보기
#1. ggplot2() 패키지의 mpg데이터를 사용할 수 있도록 불러온 후 복사본 만들기
mpg <- as.data.frame(ggplot2::mpg)
mpg <- as.data.frame(ggplot2::mpg)
mpg
#2. 복사본 데이터를 이용해 cty -> city, hwy -> highway로 수정
mpg<-rename(mpg,city=cty, highway=hwy)
mpg
mpg
View(mpg)
mpg$total<-(mpg$city+mpg$highway)/2
head(mpg)
View(mpg)
hist(mpg$total)
hist(mpg$test)
mpg$test<-ifelse(mpg$total>=20, "pass","fail")
hist(mpg,20)
head(mpg,20)
table(mpg$test)
table
qplot(mpg$test)
mpg$grade<-ifelse(mpg$total>=30,"A",ifelse(mpg$total>=20,"B","C"))
mpg$grade
head(mpg,20)
table(mpg$grade)
qplot(mpg$grade)
mpg$grade<-ifelse(mpg$total>=30,"A",
ifelse(mpg$total>=20,"B",
ifelse(mpg$total>=10,"C","D")))
table(mpg$grade)
qplot(mpg$grade)
mpg$grade<-ifelse(mpg$total>=30,"A",
ifelse(mpg$total>=25,"B",
ifelse(mpg$total>=20,"C","D")))
table(mpg$grade)
qplot(mpg$grade)
