如何在 R 的 data.table 物件列中查詢每個類別的百分比?
要在 R 中的 data.table 物件中查詢每個類別的百分比,我們可以按照以下步驟操作:
首先,建立一個 data.table 物件。
然後,在分組後使用 dplyr 包的 summarise 函式以及 n 和 nrow。
示例
建立 data.table 物件
讓我們建立一個如下所示的 data.table 物件:
library(data.table) Factor<-sample(c("very low","low","medium","high","very high"),25,replace=TRUE) Response<-rnorm(25) DT<-data.table(Factor,Response) DT
輸出
執行上述指令碼後,會生成以下輸出(由於隨機化,此輸出在您的系統上會有所不同):
Factor Response 1: low -1.61215323 2: very high -0.44482842 3: very low -0.08886876 4: very high -0.23859749 5: high 0.24527395 6: low 1.36309052 7: low 0.85434533 8: low -0.04598830 9: high -0.09693464 10: low -0.66470019 11: high -0.27726887 12: medium 0.30070368 13: very low -1.10935270 14: high 2.05570820 15: low -0.61390253 16: low 1.04354500 17: high -1.74834030 18: very low -0.84208037 19: medium 2.26732484 20: very high -0.30309612 21: low 0.72720852 22: high -2.52034038 23: very low -1.50381843 24: high -0.61927487 25: high 0.14854389 Factor Response
查詢 data.table 物件中每個類別的百分比
使用 dplyr 包的 summarise 函式,在分組後以及 n 和 nrow,以查詢 data.table 物件 DT 的 Factor 列中每個類別的百分比:
library(data.table) Factor<-sample(c("very low","low","medium","high","very high"),25,replace=TRUE) Response<-rnorm(25) DT<-data.table(Factor,Response) library(dplyr) DT %>% group_by(Factor) %>% summarise(Percent=n()/nrow(.))
輸出
# A tibble: 5 x 2 Factor Percent <chr> <dbl> 1 high 0.32 2 low 0.32 3 medium 0.08 4 very high 0.12 5 very low 0.16
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