purrr::reduceがしっくりこないメモ。
check_query <-
function (data, query){
data %>%
mutate(UQ(query) := ifelse(str_detect(Species, query), TRUE, FALSE))
}
qs <- c("s", "ver", "col")
# 引数を変えながらループする処理
result_base <-
iris[48:52,] %>%
check_query(qs[1]) %>%
check_query(qs[2]) %>%
check_query(qs[3]) %>%
knitr::kable()
result_base
# 等価なreduce
result_reduce <-
iris[48:52,] %>%
list() %>%
append(., as.list(qs)) %>%
reduce(.x = ., .f = check_query) %>%
knitr::kable()
identical(result_base, result_reduce)| Sepal.Length | Sepal.Width | Petal.Length | Petal.Width | Species | s | ver | col |
|---|---|---|---|---|---|---|---|
| 4.6 | 3.2 | 1.4 | 0.2 | setosa | TRUE | FALSE | FALSE |
| 5.3 | 3.7 | 1.5 | 0.2 | setosa | TRUE | FALSE | FALSE |
| 5.0 | 3.3 | 1.4 | 0.2 | setosa | TRUE | FALSE | FALSE |
| 7.0 | 3.2 | 4.7 | 1.4 | versicolor | TRUE | TRUE | TRUE |
| 6.4 | 3.2 | 4.5 | 1.5 | versicolor | TRUE | TRUE | TRUE |
## [1] TRUEreduce(.x = list(a, b, c, d), .f = fun)はfun(fun(fun(a, b), c), d)と等価。 .xの第一要素に第二要素以降を引数としてfunを繰り返すイメージ。
関数の被適用オブジェクト (a) と引数 (b–d) が同レベルで収納されているのは気持ち悪いうえに、pipeでつなぐと手数が増える。
aとb–dを切り分けるような形であってほしかった。
REDUCE <-
function(.x, .arg, .f){
lst(.x) %>%
append(.arg) %>%
reduce(.f)
}
set.seed(4347)
(query <- as.list(paste0(sample(letters, size = 10), sample(letters, size = 10))))
iris[48:52,] %>%
REDUCE(.arg = query, .f = check_query) %>%
knitr::kable()## [[1]]
## [1] "sa"
##
## [[2]]
## [1] "gb"
##
## [[3]]
## [1] "zi"
##
## [[4]]
## [1] "or"
##
## [[5]]
## [1] "ic"
##
## [[6]]
## [1] "fp"
##
## [[7]]
## [1] "vx"
##
## [[8]]
## [1] "xe"
##
## [[9]]
## [1] "rf"
##
## [[10]]
## [1] "ty"| Sepal.Length | Sepal.Width | Petal.Length | Petal.Width | Species | sa | gb | zi | or | ic | fp | vx | xe | rf | ty |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4.6 | 3.2 | 1.4 | 0.2 | setosa | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 5.3 | 3.7 | 1.5 | 0.2 | setosa | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 5.0 | 3.3 | 1.4 | 0.2 | setosa | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 7.0 | 3.2 | 4.7 | 1.4 | versicolor | FALSE | FALSE | FALSE | TRUE | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 6.4 | 3.2 | 4.5 | 1.5 | versicolor | FALSE | FALSE | FALSE | TRUE | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE |
Session Info
session_info()## setting value
## version R version 3.5.0 (2018-04-23)
## system x86_64, darwin15.6.0
## ui X11
## language (EN)
## collate en_US.UTF-8
## tz Australia/Brisbane
## date 2018-07-20
##
## package * version date source
## assertthat 0.2.0 2017-04-11 CRAN (R 3.5.0)
## backports 1.1.2 2017-12-13 CRAN (R 3.5.0)
## base * 3.5.0 2018-04-24 local
## bindr 0.1.1 2018-03-13 CRAN (R 3.5.0)
## bindrcpp * 0.2.2 2018-03-29 CRAN (R 3.5.0)
## blogdown 0.6 2018-04-18 CRAN (R 3.5.0)
## bookdown 0.7 2018-02-18 CRAN (R 3.5.0)
## broom * 0.4.4.9000 2018-06-21 Github (tidyverse/broom@2721de4)
## cellranger 1.1.0 2016-07-27 CRAN (R 3.5.0)
## cli 1.0.0 2017-11-05 CRAN (R 3.5.0)
## colorspace 1.3-2 2016-12-14 CRAN (R 3.5.0)
## compiler 3.5.0 2018-04-24 local
## crayon 1.3.4 2017-09-16 CRAN (R 3.5.0)
## datasets * 3.5.0 2018-04-24 local
## devtools * 1.13.5 2018-02-18 CRAN (R 3.5.0)
## digest 0.6.15 2018-01-28 CRAN (R 3.5.0)
## dplyr * 0.7.5 2018-05-19 CRAN (R 3.5.0)
## evaluate 0.10.1 2017-06-24 CRAN (R 3.5.0)
## forcats * 0.3.0 2018-02-19 CRAN (R 3.5.0)
## ggplot2 * 3.0.0.9000 2018-07-16 Github (hadley/ggplot2@79e8b45)
## glue 1.2.0 2017-10-29 CRAN (R 3.5.0)
## graphics * 3.5.0 2018-04-24 local
## grDevices * 3.5.0 2018-04-24 local
## grid 3.5.0 2018-04-24 local
## gtable 0.2.0 2016-02-26 CRAN (R 3.5.0)
## haven 1.1.1 2018-01-18 CRAN (R 3.5.0)
## highr 0.6 2016-05-09 CRAN (R 3.5.0)
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## htmltools 0.3.6 2017-04-28 CRAN (R 3.5.0)
## httr 1.3.1 2017-08-20 CRAN (R 3.5.0)
## jsonlite 1.5 2017-06-01 CRAN (R 3.5.0)
## knitr * 1.20 2018-02-20 CRAN (R 3.5.0)
## lattice 0.20-35 2017-03-25 CRAN (R 3.5.0)
## lazyeval 0.2.1 2017-10-29 CRAN (R 3.5.0)
## lubridate * 1.7.4 2018-04-11 CRAN (R 3.5.0)
## magrittr * 1.5 2014-11-22 CRAN (R 3.5.0)
## MASS * 7.3-49 2018-02-23 CRAN (R 3.5.0)
## memoise 1.1.0 2017-04-21 CRAN (R 3.5.0)
## methods * 3.5.0 2018-04-24 local
## modelr 0.1.2 2018-05-11 cran (@0.1.2)
## munsell 0.4.3 2016-02-13 CRAN (R 3.5.0)
## nlme 3.1-137 2018-04-07 CRAN (R 3.5.0)
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## Rcpp 0.12.17 2018-05-18 cran (@0.12.17)
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## reshape2 1.4.3 2017-12-11 CRAN (R 3.5.0)
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## rmarkdown 1.10 2018-06-11 cran (@1.10)
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## rvest 0.3.2 2016-06-17 CRAN (R 3.5.0)
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## stats * 3.5.0 2018-04-24 local
## stringi 1.2.3 2018-06-12 cran (@1.2.3)
## stringr * 1.3.1 2018-05-10 cran (@1.3.1)
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## yaml 2.1.19 2018-05-01 cran (@2.1.19)