데이터프레임 관련

1. 각각의 벡터를 만들고 합치는 방법

english <- c(90,80,60,70)
english
math <- c(50,60,100,20)
math

df_midterm <- data.frame(english, math)
df_midterm

klas <- c(1,1,2,2)
klas

df_midterm <- data.frame(english,math,klas)
df_midterm

> english <- c(90,80,60,70)
> english
[1] 90 80 60 70
> math <- c(50,60,100,20)
> math
[1]  50  60 100  20
> 
> df_midterm <- data.frame(english, math)
> df_midterm
  english math
1      90   50
2      80   60
3      60  100
4      70   20
> 
> class <- c(1,1,2,2)
> class
[1] 1 1 2 2

 

2. 바로 만드는 방법

df2_midterm <- data.frame(english2=c(90,80,60,70),
                          math2=c(50,60,100,20),
                          class2=c(1,1,2,2))
df2_midterm

> df2_midterm <- data.frame(english2=c(90,80,60,70),
+                           math2=c(50,60,100,20),
+                           class2=c(1,1,2,2))
> df2_midterm
  english2 math2 class2
1       90    50      1
2       80    60      1
3       60   100      2
4       70    20      2

 

3. 데이터프레임의 속성 읽기

dataframe$col

df=data.frame(var1=c(5,3,4),
              var2=c(2,6,1))
df$var1

> df=data.frame(var1=c(5,3,4),
+               var2=c(2,6,1))
> df$var1
[1] 5 3 4

 

4. 파생속성 만들기(속성추가하기)

df=data.frame(var1=c(5,3,4),
              var2=c(2,6,1))

df$var_sum=df$var1+df$var2
df$var_mean=(df$var1+df$var2)/2
df

> df=data.frame(var1=c(5,3,4),
+               var2=c(2,6,1))

> df$var_sum=df$var1+df$var2

> df$var_mean=(df$var1+df$var2)/2

> df
  var1 var2 var_sum var_mean
1    5    2       7      3.5
2    3    6       9      4.5
3    4    1       5      2.5