[R코드연습장] dplyr - rename / arrange

rename

이름처럼 변수의 이름을 바꾸는 기능. 기본 문법보다 뭐가 더 나아졌을까.

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all variable name check

# 기본으로 주어지는 mtcars 데이터프레임의 변수명을 확인했습니다. 총 11개 입니다.

names(mtcars)

 

 

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dplyr 패키지를 쓰지 않고 변수 이름을 바꿔 봅시다.

# change name _ basic method

mtcars_re1 <- mtcars

names(mtcars_re1)[c(1,2)] <- c("ab","cd")

names(mtcars_re1)

 

 

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dplyr 패키지의 select 로 변수 이름을 바꿔봅시다. select 이기 때문에 언급된 변수들만 살아남습니다. 중간에 이름을 바꾸든 뭐하든 기재된 이름의 변수만 남게 되는 거지요~

# change name _ dplyr _ select

mtcars_re2 <- mtcars

mtcars_re2 <- select(mtcars_re2, "cyl2" <- "cyl", mpg)

str(mtcars_re2)

 

 

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dplyr 패키지의 rename 으로 변수 이름을 바꿔봅시다. rename 이기 때문에 선택된 변수의 이름만 바꿔 줍니다. 변수들은 그대로 유지합니다.

# change name _ dplyr _ rename

mtcars_re3 <- mtcars

mtcars_re3 <- rename(mtcars_re3, cyl1=cyl)

names(mtcars_re3)

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arrange

특정 변수를 통한 정렬기능.

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변수를 넣으면 오름차순으로, desc() 로 내림차순 정렬이 가능하다.

mtcars_sort <- arrange(mtcars,desc(cyl))

head(mtcars_sort)

 

 

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