Computation failed in stat_summary()

[ericpgreen]

As described here, I received the following warning when I had an object in my environment called mean.

Warning message: Computation failed in stat_summary(): 'what' must be a function or character string

library(dplyr)
library(ggplot2)
set.seed(205)
dat = data.frame(t=rep(1:2, each=10), 
                 pairs=rep(1:10,2), 
                 value=rnorm(20))

ggplot(dat %>% group_by(pairs) %>%
         mutate(slope = (value[t==2] - value[t==1])/(2-1)),
       aes(t, value, group=pairs, colour=slope > 0)) +
  geom_point() +
  geom_line() +
  stat_summary(fun.y=mean,geom="line",lwd=2,aes(group=1))

A more informative warning would be helpful if possible to implement.

[hadley]

Thanks for providing some code that illustrates the problem — it's a great start 😄 However, your code is currently a bit too complicated: there's quite a bit of extraneous stuff in there that doesn't seem directly related to the problem. Can you please try and simplify your example some more? The more minimal you can make the reprex, the faster I can identify the problem and fix it.

[hadley]

I've closed this issue due to lack of requested reprex. If you still care about this bug, please open a new issue with a reprex.

[zx8754]

Adding a note as linked post is deleted at StackOverflow, the issue was caused by:

Turns out I had an object called mean in my workspace. – Eric Green Nov 30 '16 at 4:15

[klmr]

stat_summary (and similar functions that accept functions as arguments) should probably perform disambiguation internally using match.fun to avoid this issue, or at the very least give a descriptive error message.

[lock]

This old issue has been automatically locked. If you believe you have found a related problem, please file a new issue (with reprex) and link to this issue. https://reprex.tidyverse.org/