How to uses pipes?-CodePudding

I'm trying to use pipes but I think something is wrong with my syntaxis. When I write:

mean(b_2021_01$Day.of.week, na.rm=TRUE)

Everything is ok, but when I write...

b_2021_01 %>% mean(Day.of.week, na.rm=T)

An error message appears "Warning message: In mean.default(., Day.of.week, na.rm = T) : argument is not numeric or logical: returning NA"

The "Day.of.week" variable is an int, I don't understand why it says that my argument is not numeric.

CodePudding user response：

Use pull to extract the column and then use mean

library(magrittr)
b_2021_01 %>%
    pull(Day.of.week) %>%
    mean(na.rm = TRUE)

Or wrap with {}

b_2021_01 %>% 
    {mean(.$Day.of.week, na.rm=TRUE)}

Or use exposition operator (%$%)

b_2021_01 %$%
   mean(Day.of.week, na.rm = TRUE)

-testing

> mtcars %$%
    mean(mpg, na.rm = TRUE)
[1] 20.09062

The reason for the error is the first argument x should be a vector, but on the rhs of %>%, it is taken as the whole data.frame as input

> mtcars %>% mean(.$mpg, na.rm = TRUE)
[1] NA
Warning message:
In mean.default(., .$mpg, na.rm = TRUE) :
  argument is not numeric or logical: returning NA

> mean(mtcars, mtcars$mpg )
[1] NA
Warning message:
In mean.default(mtcars, mtcars$mpg) :
  argument is not numeric or logical: returning NA