CODEWITHSUNDEEP
rmagrittr
Danny
Danny

Reputation: 403

Error object "." not found when using pipe

I'm sorry if this is a repeat but I can't find it:

I'm trying to use the . placeholder with the pipe (%>%) from magrittr, and it seems not to work when it's the second call.

For instance, this works: 

data.frame(t = c(1.1,2.2,3.3), y = c(1,2,3)) %$% (t-y)^2 %>% sum(.)

But this doesn't:

data.frame(t = c(1.1,2.2,3.3), y = c(1,2,3)) %$% (t-y)^2 %>% sum(.)/length(.)

Any intuition for why this is happening? Thanks!

Danny

Upvotes: 3

Views: 1881

Answers (1)

akrun
akrun

Reputation: 886938

We need to place it inside the braces for evaluating as a unit

data.frame(t = c(1.1,2.2,3.3), y = c(1,2,3)) %$%
          (t-y)^2 %>% 
          {sum(.)/length(.)} 
#[1] 0.04666667

which is the same as mean

data.frame(t = c(1.1,2.2,3.3), y = c(1,2,3)) %$%
      (t-y)^2 %>% 
      mean
#[1] 0.04666667

Upvotes: 2

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