Peter Drake, he/him, LFHCfS 🔥 @peterdrake@social.cleverlibre.org

@matt1126

I still don't understand how, in

b %>% mutate(m=mean(post, na.rm=TRUE))

mean figures out that "post" is really "b$post". It's as if mutate has made a substitution here.

@matt1126

b %>% mutate(post=revised) works in the second section, but the next two lines after the "Why doesn't this work?" comment give errors.

I understand that in

b %>% mutate(m=mean(post, na.rm=TRUE))

mutate is taking an implicit first argument b, so this is equivalent to:

mutate(b, m=mean(post, na.rm=TRUE))

What confuses me here is mean. Is it taking an implicit first argument b?

If so, why doesn't

mean(b, post, na.rn=TRUE)

work?

If not, how does mean know where to find post?

It appears that mean is not a normal function, but some special thing that only works in the context of something like mutate.

@logoninternet When I was in high school one candidate ate a live goldfish as part of her presentation. She lost.

#Rstats mystery

library(tidyverse)

b <- tibble(pre=c(8,8,5,3), post=c(8, 8, 5, NA))

# This works
b %>% mutate(post = if_else(is.na(post), mean(post, na.rm=TRUE), post))

# But what if that expression is too hairy for the student? In other languages,
# you can separate out and name the parts. You can do that in R by using the
# completely different $ syntax:
mean_of_others <- mean(b$post, na.rm=TRUE)
revised <- if_else(is.na(b$post), mean_of_others, b$post)
b %>% mutate(post = revised)

# Why doesn't this work? Do mean and if_else not work with the pipe unless they
# are inside something like mutate?
mean_of_others <- b %>% mean(post, na.rm=TRUE) # Error!
revised <- b %>% if_else(is.na(post), mean_of_others, post) # Error!
b %>% mutate(post = revised)

#Rstats seems to have missed this memo:

"Orthogonality in a programming language means that a relatively small set of primitive constructs can be combined in a relatively small number of ways to build the control and data structures of the language.[2] It is associated with simplicity; the more orthogonal the design, the fewer exceptions. This makes it easier to learn, read and write programs in a programming language[citation needed]. The meaning of an orthogonal feature is independent of context; the key parameters are symmetry and consistency (for example, a pointer is an orthogonal concept)."

https://en.wikipedia.org/wiki/Orthogonality_(programming)

Our class time slots are 8-9, 9:10-10:10, 10:20-11:20, etc. During my 9:10 class, my addled brain saw the clock approaching :50 and ended the class 20 minutes early.

Nobody stopped me.

Future nonbinary monarch: *chooses they/them pronouns*

Transphobe: That doesn't make sense! "They" is plural!

Monarch: We don't see the problem.

With the change in monarch, the Royal Navy will have to scrape "HMS" off all of the ships and instead paint on "HMS".

For legitimate pedagogical reasons, I just searched my Google Drive for "dank".

Show: I Love Lucy
Guest: KISS
Song: "I Was Made for Babalu"

#MisrememberedTvMusicalGuests

Show: The Muppet Show
Guest: Sylvester Stallone
Song: "The Rambo Connection"

#MisrememberedTvMusicalGuests

Daybreak, Matt Leacock's new board game about climate change, looks fun, hopeful, and educational.

https://www.backerkit.com/c/alex-hague/daybreak

#BoardGames #climate

For today, the character '|' will be pronounced "hornpipe" and the data type "double" will be pronounced "doubloon".

Avast, me hearties! Heave to and prepare to be boarded!

#itlapd #pirate