conditional subsetting from data.frame in R

Question

I have a data.frame HERE. I was wondering how I can subset variables named as dot.names (see below) for rows in the data.frame for which variable control is FALSE AND alphabetically order the answer based on D$study.name in BASE R?

Here is the code I used without success:

D <- read.csv("https://raw.githubusercontent.com/izeh/m/master/k.csv") # data.frame

dot.names <- c("ESL", "prof" ,"scope", "type")             

D[dot.names & !control]

Shree · Accepted Answer · 2019-08-13 02:07:55Z

1

If D$control is a logical column -

res1 <- D[order(D$study.name), ]

res2 <- res1[!res1$control, dot.names]

If D$control is character column -

D[D$control == "FALSE", dot.names]

A on-liner using subset -

subset(D[order(D$study.name), ], !control, select = dot.names)

With dplyr -

D %>% 
  filter(!control) %>% 
  arrange(study.name) %>% 
  select(dot.names)

edited Aug 13, 2019 at 2:07

answered Aug 13, 2019 at 1:33

Shree

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2 Comments

Shree Over a year ago

@rnorouzian They should be. Try-

dot.names <- c("mpg", "hp"); res1 <- mtcars[order(mtcars$wt), ];  res2 <- res1[res1$cyl == 4, dot.names];  res3 <- subset(mtcars[order(mtcars$wt), ], cyl == 4, select = dot.names);  identical(res2, res3);  all.equal(res2, res3)

.Also try all.equal(). Identical is very strict I think. Let me know.

rnorouzian Over a year ago

I think your solutions are not identical nrow for your subset solution gives 33 rows, BUT nrow for your res2 solution gives 40 rows !!!

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