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Jennifer (Jenny) Bryan created this gist
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This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,71 @@ #' --- #' output: #' html_document: #' keep_md: TRUE #' --- #+ include = FALSE library(dplyr) #' Responses to [my #' tweet](https://twitter.com/JennyBryan/status/599379158452416512): #' "Help me use dplyr to do this less awkwardly? #rstats" mtcars %>% group_by(cyl) %>% summarize(vs0 = sum(vs == 0), vs1 = sum(vs == 1)) #' Later clarified:"imagine `vs` had 7 levels instead of 2 … how to do for a #' general factor … general cross-tabulation" #' #' The #rstats twitterati delivered some great answers! library(dplyr) library(tidyr) ## spread() library(reshape2) ## dcast(), melt() library(data.table) #' @noamross mtcars %>% group_by(cyl, vs) %>% summarize(count = n()) %>% spread(vs, count) #' @tjmahr: "skip summarise(count = n()) and use tally() or count()" mtcars %>% group_by(cyl, vs) %>% tally() %>% spread(vs, n) #' @dev_dmu mtcars %>% count(cyl, vs) %>% spread(vs, n) #' @tylerrinker dcast(melt(mtcars[, c("cyl", "vs")], id = "cyl"), cyl ~ value) #' @daroczig dplyr, reshape2 mtcars %>% group_by(cyl, vs) %>% summarize(n()) %>% dcast(cyl ~ vs) #' @daroczig data.table, reshape2 mtcarsDT <- mtcars %>% data.table() dcast(mtcarsDT[, .N, by = list(cyl, vs)], cyl ~ vs) #' @MattDowle data.table, reshape2, %>% mtcarsDT[, .N, .(cyl, vs)] %>% dcast(cyl ~ vs) #' @dev_dmu bonus content: proportions! mtcars %>% count(cyl, vs) %>% #mutate(prop = n/sum(n)) mutate(prop = prop.table(n)) mtcars %>% count(cyl, vs) %>% mutate(prop = prop.table(n)) %>% select(-n) %>% spread(vs, prop) This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,222 @@ Responses to [my tweet](https://twitter.com/JennyBryan/status/599379158452416512): "Help me use dplyr to do this less awkwardly? #rstats" ```r mtcars %>% group_by(cyl) %>% summarize(vs0 = sum(vs == 0), vs1 = sum(vs == 1)) ``` ``` ## Source: local data frame [3 x 3] ## ## cyl vs0 vs1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 0 ``` Later clarified:"imagine `vs` had 7 levels instead of 2 … how to do for a general factor … general cross-tabulation" The #rstats twitterati delivered some great answers! ```r library(dplyr) library(tidyr) ## spread() library(reshape2) ## dcast(), melt() library(data.table) ``` ``` ## ## Attaching package: 'data.table' ## ## The following objects are masked from 'package:dplyr': ## ## between, last ``` @noamross ```r mtcars %>% group_by(cyl, vs) %>% summarize(count = n()) %>% spread(vs, count) ``` ``` ## Source: local data frame [3 x 3] ## ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @tjmahr: "skip summarise(count = n()) and use tally() or count()" ```r mtcars %>% group_by(cyl, vs) %>% tally() %>% spread(vs, n) ``` ``` ## Source: local data frame [3 x 3] ## ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @dev_dmu ```r mtcars %>% count(cyl, vs) %>% spread(vs, n) ``` ``` ## Source: local data frame [3 x 3] ## ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @tylerrinker ```r dcast(melt(mtcars[, c("cyl", "vs")], id = "cyl"), cyl ~ value) ``` ``` ## Aggregation function missing: defaulting to length ``` ``` ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 0 ``` @daroczig dplyr, reshape2 ```r mtcars %>% group_by(cyl, vs) %>% summarize(n()) %>% dcast(cyl ~ vs) ``` ``` ## Using n() as value column: use value.var to override. ``` ``` ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @daroczig data.table, reshape2 ```r mtcarsDT <- mtcars %>% data.table() dcast(mtcarsDT[, .N, by = list(cyl, vs)], cyl ~ vs) ``` ``` ## Using N as value column: use value.var to override. ``` ``` ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @MattDowle data.table, reshape2, %>% ```r mtcarsDT[, .N, .(cyl, vs)] %>% dcast(cyl ~ vs) ``` ``` ## Using N as value column: use value.var to override. ``` ``` ## cyl 0 1 ## 1 4 1 10 ## 2 6 3 4 ## 3 8 14 NA ``` @dev_dmu bonus content: proportions! ```r mtcars %>% count(cyl, vs) %>% #mutate(prop = n/sum(n)) mutate(prop = prop.table(n)) ``` ``` ## Source: local data frame [5 x 4] ## Groups: cyl ## ## cyl vs n prop ## 1 4 0 1 0.09090909 ## 2 4 1 10 0.90909091 ## 3 6 0 3 0.42857143 ## 4 6 1 4 0.57142857 ## 5 8 0 14 1.00000000 ``` ```r mtcars %>% count(cyl, vs) %>% mutate(prop = prop.table(n)) %>% select(-n) %>% spread(vs, prop) ``` ``` ## Source: local data frame [3 x 3] ## ## cyl 0 1 ## 1 4 0.09090909 0.9090909 ## 2 6 0.42857143 0.5714286 ## 3 8 1.00000000 NA ``` --- title: "2015-05-15_cross-tabulation.R" author: "jenny" date: "Fri May 15 22:15:58 2015" ---
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