[R코드연습장] dplyr - sample

sample

뭐,, 쓸일이 있을랑가 보르겠는데, 샘플 추출(임의로 row 선택) 방법입니다.

---

1) sample_n n개의 row를 추출 합니다.

#nrow(mtcars)

sample_n(mtcars,3) #3개

#sample_frac(mtcars,0.10)

#mtcars %>% group_by(cyl) %>% sample_n(2)

 

 

---

2) sample_frac 총 row 개수 중에 n%의 row를 추출 합니다.

#nrow(mtcars)

#sample_n(mtcars,3)

sample_frac(mtcars,0.10) #10%

#mtcars %>% group_by(cyl) %>% sample_n(2)

 

 

---

3) group_by 샘플을 추출하기 전에 특정 변수의 그룹별로 할건지 설정할 수 있습니다.

#nrow(mtcars)

#sample_n(mtcars,3)

#sample_frac(mtcars,0.10)

mtcars %>% group_by(cyl) %>% sample_n(2) #cyl을 기준으로 2개씩

 

 

%23%20title%0A@%5B%uD2F0%uC2A4%uD1A0%uB9AC%5D%0A%0A%21%5BAlt%20text%5D%28./20180315125705.png%29%0A%0A%23%23%23%20sample%0A%uBB50%2C%2C%20%uC4F8%uC77C%uC774%20%uC788%uC744%uB791%uAC00%20%uBCF4%uB974%uACA0%uB294%uB370%2C%20%20%uC0D8%uD50C%20%uCD94%uCD9C%28%uC784%uC758%uB85C%20row%20%uC120%uD0DD%29%20%uBC29%uBC95%uC785%uB2C8%uB2E4.%20%0A%0A------%0A%0A%3E%201%29%20%20%60sample_n%60%20n%uAC1C%uC758%20row%uB97C%20%uCD94%uCD9C%20%uD569%uB2C8%uB2E4.%20%0A%60%60%60r%0A%23nrow%28mtcars%29%0Asample_n%28mtcars%2C3%29%0A%23sample_frac%28mtcars%2C0.10%29%0A%23mtcars%20%25%3E%25%20group_by%28cyl%29%20%25%3E%25%20sample_n%282%29%0A%60%60%60%0A%0A%21%5BAlt%20text%5D%28./20180315152127.png%29%0A%0A------%0A%0A%0A%0A%0A%3E%202%29%20%20%60sample_frac%60%20%uCD1D%20row%20%uAC1C%uC218%20%uC911%uC5D0%20n%25%uC758%20row%uB97C%20%uCD94%uCD9C%20%uD569%uB2C8%uB2E4.%20%0A%60%60%60r%0A%23nrow%28mtcars%29%0A%23sample_n%28mtcars%2C3%29%0Asample_frac%28mtcars%2C0.10%29%0A%23mtcars%20%25%3E%25%20group_by%28cyl%29%20%25%3E%25%20sample_n%282%29%0A%60%60%60%0A%21%5BAlt%20text%5D%28./20180315152138.png%29%0A%0A------%0A%0A%0A%0A%0A%3E%203%29%20%20%60group_by%60%20%uC0D8%uD50C%uC744%20%uCD94%uCD9C%uD558%uAE30%20%uC804%uC5D0%20%uD2B9%uC815%20%uBCC0%uC218%uC758%20%uADF8%uB8F9%uBCC4%uB85C%20%uD560%uAC74%uC9C0%20%uC124%uC815%uD560%20%uC218%20%uC788%uC2B5%uB2C8%uB2E4.%0A%60%60%60r%0A%23nrow%28mtcars%29%0A%23sample_n%28mtcars%2C3%29%0A%23sample_frac%28mtcars%2C0.10%29%0Amtcars%20%25%3E%25%20group_by%28cyl%29%20%25%3E%25%20sample_n%282%29%0A%60%60%60%0A%0A%21%5BAlt%20text%5D%28./20180315152147.png%29%0A