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[英]How do I apply a function to specific columns in a dataframe and replace the original columns?
[英]How do I apply function to specific columns
我有一個示例數據框,如下所示:
well <- c('A1','A2','A3','A4','A5')
area <- c(21000, 23400, 26800,70000,8000)
length <- c(21, 234, 26,70,22)
group<-c('WT','Control','C2','D2','E1')
data <- data.frame(well,area,length,group)
我想應用下面的 function 從數據框中刪除具有異常值的行:
Outlier <- function(x){
low <- median(x, na.rm=TRUE)-5*(mad(x))
high <- median(x, na.rm=TRUE)+5*(mad(x))
out <- if_else(x > high, NA,ifelse(x < low, low, x))
out }
如何將此 function 應用於 dataframe,不包括某些列,例如列“well”和“group”?
我們可以在base R
中使用lapply
data[c('area', 'length')] <- lapply(data[c('area', 'length')], Outlier)
或與dplyr
library(dplyr) # 1.0.0
data %>%
mutate(across(area:length, Outlier))
# well area length group
#1 A1 21000 21 WT
#2 A2 23400 NA Control
#3 A3 26800 26 C2
#4 A4 NA NA D2
#5 A5 8000 22 E1
注意:確保在“異常值”function 中將NA
更改為NA_real_
Outlier <- function(x){
low <- median(x, na.rm=TRUE)-5*(mad(x))
high <- median(x, na.rm=TRUE)+5*(mad(x))
out <- if_else(x > high, NA_real_,ifelse(x < low, low, x))
out }
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