[英]Apply self-defined function on list of data frames in R
This is a follow-up to a previous question of mine: Code in R to conditionally subtract columns in data frames这是我之前的问题的后续: R 中的代码以有条件地减去数据帧中的列
I now want to apply the given solution to my previous problem我现在想将给定的解决方案应用于我以前的问题
cols <- grep('^\\d+$', names(df), value = TRUE)
new_cols <- paste0(cols, '_corrected')
df[new_cols] <- df[cols] - df[paste0('Background_', cols)]
df[c("Wavelength", new_cols)]
to every data frame in a list.到列表中的每个数据框。 I import all sheets of an excel file so that every sheet becomes one data frame in a list using this code (courtesy of Read all worksheets in an Excel workbook into an R list with data.frames 's top answer):
我导入 excel 文件的所有工作表,以便使用此代码将每个工作表都变成列表中的一个数据框(由Read all worksheets in an Excel workbook into an ZE1E1D3D40573127E9EE0480CAF1 提供)
read_excel_allsheets <- function(filename, tibble = FALSE) {
sheets <- readxl::excel_sheets(filename)
x <- lapply(sheets, function(X) readxl::read_excel(filename, sheet = X))
if(!tibble) x <- lapply(x, as.data.frame)
names(x) <- sheets
x
}
mysheets <- read_excel_allsheets(file.choose())
How do I apply the first code box to my data frame list?如何将第一个代码框应用于我的数据框列表?
I want to get from something like this:我想从这样的事情中得到:
df_1 <- structure(list(Wavelength = 300:301, Background_1 = c(5L, 3L),
`1` = c(11L, 12L), Background_2 = c(4L, 5L), `2` = c(12L, 10L)),
class = "data.frame", row.names = c(NA, -2L))
df_2 <- structure(list(Wavelength = 300:301, Background_1 = c(6L, 4L),
`1` = c(10L, 13L), Background_2 = c(5L, 6L), `2` = c(11L, 11L),
Background_3 = c(4L, 6L), `3` = c(13L, 13L)),
class = "data.frame", row.names = c(NA, -2L))
df_list <- list(df_1, df_2)
To something like this:对于这样的事情:
df_1_corrected <- structure(list(Wavelength = 300:301, `1_corrected` = c(6L, 9L),
`2_corrected` = c(8L, 5L)),
class = "data.frame", row.names = c(NA, -2L))
df_2_corrected <- structure(list(Wavelength =300:301, `1_corrected` = c(4L, 9L),
`2_corrected` = c(6L, 5L),
`3_corrected` = c(9L, 7L)),
class = "data.frame", row.names = c(NA, -2L))
df_corrected_list <- list(df_1_corrected, df_2_corrected)
actual data excerpt实际数据摘录
Wavelength Background 1 1 Background 2 2 Background 3 3
300 273290.0 337670.0 276740.0 397530 288500.0 367480.0
301 299126.7 375143.3 299273.3 432250 310313.3 394796.7
I have read the lapply
function would be used for this but i have never used it before, as I am quite the beginner in R.我已经阅读了
lapply
function 将用于此,但我以前从未使用过它,因为我是 R 的初学者。 Help is much appreciated!非常感谢您的帮助!
You can put the code in a function and apply it for each dataframe in list using lapply
:您可以将代码放入 function 并使用 lapply 将其应用于列表中的每个
lapply
:
subtract_values <- function(df) {
cols <- grep('^\\d+$', names(df), value = TRUE)
new_cols <- paste0(cols, '_corrected')
df[new_cols] <- df[cols] - df[paste0('Background ', cols)]
df[c("Wavelength", new_cols)]
}
lapply(df_list, subtract_values)
#[[1]]
# Wavelength 1_corrected 2_corrected
#1 300 6 8
#2 301 9 5
#[[2]]
# Wavelength 1_corrected 2_corrected 3_corrected
#1 300 4 6 9
#2 301 9 5 7
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