Meeting chat log
00:39:35 Jon Harmon (jonthegeek): .Machine$double.eps
00:40:36 Jon Harmon (jonthegeek): > .Machine$integer.max
[1] 2147483647
00:41:23 Federica Gazzelloni: ?`.Machine`
00:42:11 Ryan Metcalf: Some really fun reading about CPU “inner” workings: https://www.geeksforgeeks.org/computer-organization-von-neumann-architecture/
00:42:35 Jon Harmon (jonthegeek): > typeof(.Machine$integer.max + 1)
[1] "double"
00:42:55 Jon Harmon (jonthegeek): > .Machine$integer.max + 1L
[1] NA
Warning message:
In .Machine$integer.max + 1L : NAs produced by integer overflow
00:43:52 Becki R. (she/her): thanks for the link, Ryan!
00:44:44 Jon Harmon (jonthegeek): > sqrt(2)**2 == 2
[1] FALSE
00:45:16 Jon Harmon (jonthegeek): > dplyr::near(sqrt(2)**2, 2)
[1] TRUE
00:57:52 Ryan Metcalf: Not directly related to Cache or RAM….But similar. It is where you get FAT, FAT32, NTFS, ExFat, EXT, EXT3, etc…etc… there are hundreds of file allocation.
00:59:29 Sandra Muroy: thanks Ryan!
01:02:08 Becki R. (she/her): I'm finding the info on computer architecture (?) fascinating so I appreciate the detour.
01:03:05 Sandra Muroy: I'm glad :)
01:10:01 Ryan Metcalf: I think I just had an epiphany!!! Is this were the “Big Endian” and “Little Endian” comes in? The leading bit representing positive and negative?
01:10:27 Jon Harmon (jonthegeek): > typeof(0L)
[1] "integer"
01:12:42 Jon Harmon (jonthegeek): > .Machine$double.xmax
[1] 1.797693e+308
01:15:53 Jon Harmon (jonthegeek): > 1:10 + 1
[1] 2 3 4 5 6 7 8 9 10 11
01:16:19 Jon Harmon (jonthegeek): > 1:10 + 2:11
[1] 3 5 7 9 11 13 15 17 19 21
Meeting chat log
00:03:09 Becki R. (she/her): I have a buzz in my audio so I'm staying muted.
00:30:48 Federica Gazzelloni: http://adv-r.had.co.nz/Subsetting.html
00:33:31 Jon Harmon (jonthegeek): mtcars["mpg"]
mtcars[["mpg"]]
00:35:19 Jon Harmon (jonthegeek): months <- purrr::set_names(month.name, month.abb)
00:35:40 Jon Harmon (jonthegeek): months["Jan"]
00:35:46 Jon Harmon (jonthegeek): Jan
"January"
00:36:10 Jon Harmon (jonthegeek): > months[["Jan"]]
[1] "January"
00:38:28 Federica Gazzelloni: it acts like unlist()
00:38:48 Jon Harmon (jonthegeek): > unlist(mtcars["mpg"])
mpg1 mpg2 mpg3 mpg4 mpg5 mpg6 mpg7 mpg8 mpg9 mpg10 mpg11 mpg12 mpg13 mpg14
21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2
mpg15 mpg16 mpg17 mpg18 mpg19 mpg20 mpg21 mpg22 mpg23 mpg24 mpg25 mpg26 mpg27 mpg28
10.4 10.4 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4
mpg29 mpg30 mpg31 mpg32
15.8 19.7 15.0 21.4
00:39:13 Jon Harmon (jonthegeek): > unname(unlist(mtcars["mpg"]))
[1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2 10.4 10.4
[17] 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4 15.8 19.7 15.0 21.4
00:39:29 Jon Harmon (jonthegeek): single <- mtcars["mpg"]
00:39:50 Jon Harmon (jonthegeek): > attributes(single) <- NULL
> single
[[1]]
[1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2 10.4 10.4
[17] 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4 15.8 19.7 15.0 21.4
00:42:51 Jon Harmon (jonthegeek): > str(months[[1]])
chr "January"
> str(months[1])
Named chr "January"
- attr(*, "names")= chr "Jan"
00:43:41 Jon Harmon (jonthegeek): ?`[`
00:44:15 Jon Harmon (jonthegeek): The most important distinction between [, [[ and $ is that the [ can select more than one element whereas the other two select a single element.
00:47:28 Ryan Metcalf: BRB
00:56:31 Jon Harmon (jonthegeek): The tangent I obsessed on just now:
> pillar:::glimpse.default
function (x, width = NULL, max.level = 3, ...)
{
str(x, width = get_width_glimpse(width), max.level = max.level,
...)
invisible(x)
}
(huh, "glimpse" technically comes from the {pillar} package)
01:12:09 Jon Harmon (jonthegeek): > round(c(1.5, 2.5, 3.5, 4.5))
[1] 2 2 4 4
01:14:08 Jon Harmon (jonthegeek): Note that for rounding off a 5, the IEC 60559 standard (see also ‘IEEE 754’) is expected to be used, ‘go to the even digit’. Therefore round(0.5) is 0 and round(-1.5) is -2. However, this is dependent on OS services and on representation error (since e.g. 0.15 is not represented exactly, the rounding rule applies to the represented number and not to the printed number, and so round(0.15, 1) could be either 0.1 or 0.2).