如何在R中使用单个函数引用列表的所有组件？

Question

I have split my df into a list containing 500 groups thus:

c1=cut(SNP_Allele_Frequency$College_SE,500)
splitc1=split(SNP_Allele_Frequency,c1,drop=FALSE)

I need to find the mean for a variable for all the 500 groups (levels) contained in the list CL. Instead of repeating the process 500 times (as below), is there a way I can do this with one function?

mean(splitc1[[1L]]$ACB)....mean(splitc1[[2L]]$ACB)...
mean(splitc1[[500L]]$ACB)

Answer 1

First let's make some reproducible data:

set.seed(24)
SNP_Allele_Frequency <- data.frame(College_SE = rnorm(1000), ACB = rnorm(1000))

Now using your original method:

c1 <- cut(SNP_Allele_Frequency$College_SE, 50)
splitc1 <- split(SNP_Allele_Frequency, c1, drop = FALSE)
lapply(splitc1, function(x) mean(x[["ACB"]]))

We could do it more cleanly in dplyr :

library(dplyr)
SNP_Allele_Frequency %>% mutate(c1 = cut(SNP_Allele_Frequency$College_SE, 50)) %>%
                         group_by(c1) %>%
                         summarise(meanACB = mean(ACB))