25.20 Meeting Videos

25.20.1 Cohort 5

Meeting chat log
00:24:22    Jon Harmon (jonthegeek):    Famous computer science quote: There are only two hard things in Computer Science: cache invalidation and naming things.

-- Phil Karlton
00:32:31    Jon Harmon (jonthegeek):    > identical(1.0, 1L)
[1] FALSE
00:32:50    Jon Harmon (jonthegeek):    > 1.0 == 1L
[1] TRUE
00:33:31    Jon Harmon (jonthegeek):    identical(as.integer(1.0), 1L)
00:33:49    Jon Harmon (jonthegeek):    identical(1.0, as.double(1L))
00:38:39    Njoki Njuki Lucy:   is there a difference between ifelse() and if, else function?
00:39:32    Jon Harmon (jonthegeek):    ifelse()
if … else if … else
00:40:15    Jon Harmon (jonthegeek):    ifelse(c(TRUE, FALSE, TRUE), "yes", "no")
00:40:28    Jon Harmon (jonthegeek):    > ifelse(c(TRUE, FALSE, TRUE), "yes", "no")
[1] "yes" "no"  "yes"
00:40:52    Jon Harmon (jonthegeek):    > ifelse(1:10 == 8, "it's 8", "it isn't")
 [1] "it isn't" "it isn't" "it isn't" "it isn't" "it isn't" "it isn't" "it isn't"
 [8] "it's 8"   "it isn't" "it isn't"
00:41:12    Jon Harmon (jonthegeek):    > ifelse(1:10 == 8, 8, NA)
 [1] NA NA NA NA NA NA NA  8 NA NA
00:42:13    Ryan Metcalf:   Possible Reference, Section 7.4, Missing Values. It makes a reference to `ifelse()` function: https://r4ds.had.co.nz/exploratory-data-analysis.html?q=ifelse()#missing-values-2
00:43:01    Jon Harmon (jonthegeek):    if else
ifelse
if_else
00:43:17    Njoki Njuki Lucy:   thank you!
00:43:22    Njoki Njuki Lucy:   big time:)
00:50:35    Njoki Njuki Lucy:   what exactly is the trim doing? I didn't understand
00:52:05    Jon Harmon (jonthegeek):    > mean(c(1, 90:100), trim = 0)
[1] 87.16667
> mean(c(1, 90:100), trim = 0.1)
[1] 94.5
> mean(c(1, 90:100), trim = 0.5)
[1] 94.5
00:52:46    Jon Harmon (jonthegeek):    > mean(1:10, trim = 0.5)
[1] 5.5
00:54:10    Njoki Njuki Lucy:   okay, understood. thanks!
00:58:15    Jon Harmon (jonthegeek):    myfun <- function(x, ...) {
  mean(x, ...)
}
00:58:47    Jon Harmon (jonthegeek):    > myfun(1:10, trim = 0.1)
[1] 5.5
00:59:13    Jon Harmon (jonthegeek):    > myfun(1:10, trim = 0.1)
Error in myfun(1:10, trim = 0.1) : unused argument (trim = 0.1)
01:01:34    Jon Harmon (jonthegeek):    myfun <- function(x, funname, ...) {
  if (funname == "mean") {
    mean(x, ...)
  } else {
    log(x, ...)
  }
}
01:04:11    Jon Harmon (jonthegeek):    myfun <- function(...) {
  dots <- list(...)
  names(dots)
}

myfun(a = 1)
01:05:28    Jon Harmon (jonthegeek):    [1] "a"
01:05:49    Jon Harmon (jonthegeek):    dots <- list(a = 1)
01:09:32    Jon Harmon (jonthegeek):    myfun <- function(a, b) {
  a
}
myfun(1:10, Sys.sleep(60))
Meeting chat log
See Chapter 20 for the part of the log that's relevant to that chapter.

25.20.2 Cohort 6

Meeting chat log
00:23:48    Daniel Adereti: Range() function in R returns the maximum and minimum value of the vector and column of the dataframe in R. range() function of the column of dataframe
00:45:42    Daniel Adereti: My guess for the inf, -inf is just to assign the respective 1 and 0 to the inf and -inf
00:46:26    Daniel Adereti: and to rescale the x vector expressing all variables with inf as 1 and -inf as 0
00:58:38    Adeyemi Olusola:    Thanks for the wonderful talk. Sorry, I have to drop off now. Thanks
00:58:41    Daniel Adereti: it might make sense to stop at 19.2
Meeting chat log
00:03:15    Marielena Soilemezidi:  Hello there! :)
00:03:51    Daniel: Hello!
00:32:16    Daniel: I think it aim to check if any of the vector characters == 8, if yes, it returns 8, if no, it returns "Not available"
00:44:24    Daniel: Hello all, please remember we need volunteers for next week's class: Vectors

25.20.3 Cohort 7

Meeting chat log
00:15:05    Oluwafemi Oyedele:  start
00:58:23    Oluwafemi Oyedele:  https://dplyr.tidyverse.org/articles/programming.html
00:58:37    Oluwafemi Oyedele:  https://tidyr.tidyverse.org/articles/programming.html
00:58:47    Oluwafemi Oyedele:  https://rlang.r-lib.org/reference/topic-data-mask.html
00:58:54    Oluwafemi Oyedele:  https://ggplot2-book.org/programming.html
00:59:01    Oluwafemi Oyedele:  https://style.tidyverse.org/functions.html
00:59:43    Oluwafemi Oyedele:  stop

25.20.4 Cohort 8

Meeting chat log
00:10:01    Abdou:  Hi everyone
00:10:12    Shamsuddeen Hassan Muhammad:    hello
00:10:31    Shamsuddeen Hassan Muhammad:    Ahmad can hear me
00:10:37    Shamsuddeen Hassan Muhammad:    Abdul we can hear you
00:10:46    Abdou:  No
00:10:54    Shamsuddeen Hassan Muhammad:    Can u hear me Abduol?
00:11:07    Abdou:  No I can’t
00:11:12    Shamsuddeen Hassan Muhammad:    Re-join
00:14:21    Ahmed Mamdouh:  Start
00:47:09    Abdou:  Stop