# NOT RUN {
library(dplyr, warn.conflicts = FALSE)
mtcars2 <- lazy_dt(mtcars)
mtcars2
mtcars2 %>% select(mpg:cyl)
mtcars2 %>% select(x = mpg, y = cyl)
mtcars2 %>% filter(cyl == 4) %>% select(mpg)
mtcars2 %>% select(mpg, cyl) %>% filter(cyl == 4)
mtcars2 %>% mutate(cyl2 = cyl * 2, cyl4 = cyl2 * 2)
mtcars2 %>% transmute(cyl2 = cyl * 2, vs2 = vs * 2)
mtcars2 %>% filter(cyl == 8) %>% mutate(cyl2 = cyl * 2)
by_cyl <- mtcars2 %>% group_by(cyl)
by_cyl %>% summarise(mpg = mean(mpg))
by_cyl %>% mutate(mpg = mean(mpg))
by_cyl %>% filter(mpg < mean(mpg)) %>% summarise(hp = mean(hp))
# }
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