Question

我想快速浏览数据框中的列类，我创建了这个函数来打印列名并按类排列。我想让它告诉我不是类因子的列数。

columnsclass<-function (x){
a<-vector()
b<-vector(mode="character")
c<-vector
c=0
for (i in 1:dim(x)[2]){
a[i]<-paste(class(x[,i]),names(x)[i],sep="--")
if (class(x[,i])!= "factor"){
c<-c+1
b[c]<<-i
}}
#1st print
print(sort(a))
#2nd print
print(paste("columns that aren't factors are number:",paste(b,collapse=","),collapse="  "))    
}

然而，当我运行它时，虽然代码已经有效，但它没有进行＃2nd打印。

> columnsclass(cars) 
[1] "numeric--dist"  "numeric--speed"
[1] "columns that aren't factors are number: "
#it doesn't print the numbers of columns of class factor but if i run it separately ,it  runs
> print(paste("columns that aren't factors are   number:",paste(b,collapse=","),collapse="  "))
[1] "columns that aren't factors are number: 1,2"

Answer 1

这是一个考虑到皮埃尔评论的函数，但也简化了a的计算：

columnsclass <- function(x){
  nm <- sapply(x, class)
  a <- paste(nm, names(nm), sep = "--")
  b <- which(!sapply(x, is.factor))
  # 1st print
  print(sort(a))
  # 2nd print
  print(paste("columns that aren't factors are number:", 
    paste(b, collapse = ","), collapse = "  "))    
}
> columnsclass(cars)
[1] "numeric--dist"  "numeric--speed"
[1] "columns that aren't factors are number: 1,2"

Answer 2

str功能怎么样？

library(datasets)
data(iris)
str(iris)

如何快速浏览数据框中所有列的类？

2 个答案: