使用 sapply 时如何使用函数的参数? [英] How do I use arguments of a function when using sapply?

问题描述

我有一个数据集，它是我使用 gdata 包中的 cbindX 函数通过列绑定创建的.此功能允许我绑定具有不同行数的列.因此，当特定列中没有值时，会引入 NA.现在，我想计算每列的标准偏差.我尝试使用

I have a dataset which I created by column binding using the cbindX function from the gdata package. This function allows me to bind columns with different numbers of rows. So, NA's are introduced when there are no values in a particular column. Now, I want to calculate the standard deviation for each column. I tried using

sapply(dataset,sd)

这将返回所有行都带有值的列的标准偏差，以及行数较少的列的 NA 的标准偏差.我尝试将 na.rm 参数与 sd 函数一起使用:

This returns the standard deviation for the column having all rows with values and NA for the columns having fewer rows. I tried using the na.rm argument with the sd function:

sapply(dataset,sd(na.rm=T))

并收到错误信息

Error in is.data.frame(x) : argument "x" is missing, with no default

例如:

  firstcol <- matrix(c(1:150),ncol=1)
    secondcol <- matrix(c(1:300),ncol=1)
     thirdcol <- matrix(c(1:450),ncol=1)
      fourthcol <- matrix(c(1:600),ncol=1)
        fifthcol <- matrix(c(1:30),ncol=1)
         sixthcol <- matrix(c(1:30),ncol=1)
          seventhcol <- matrix(c(1:30),ncol=1)      


library(gdata)
  allcolscomb <- data.frame(cbindX   (firstcol,secondcol,thirdcol,fourthcol,fifthcol,sixthcol,seventhcol))      

 names(allcolscomb) <- c("1stcol","2ndcol","3rdcol","4thcol","5thcol","6thcol","7thcol")      


        sapply(allcolscomb,sd)

      sapply(allcolscomb,sd(na.rm=T))

如何使用 sapply 函数计算标准偏差?

How can I compute standard deviation using the sapply function?

推荐答案

您应该阅读 ?sapply 手册.下面是带有一些额外参数的 sapply 示例:

You should read ?sapply manual. Below example of sapply with some extra arguments:

sapply(allcolscomb, sd, na.rm=TRUE)
sapply(allcolscomb, function(x) sd(x, na.rm=TRUE))

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