R sapply name to graph x axis

Question

I'm using this function to get some exploratory analysis in r

nums <- sapply(db, is.numeric)
sapply(db[,nums], function(x) {
  nome <- as.character(names(x))
  hist(x)
  lines(density(x, na.rm = T))

  })

How can i print the name of the column in the plot as x axis? I've tried with apply over matrix by column - any way to get column name? but I can't figure out the second part of the function to make it work in this case

it's a database with both numeric and factors, so the function which assigns to nums will return a vector with TRUE if numeric and FALSE with factor columns respectively, i'll try to give some data sample — GGA, Apr 15 '16 at 13:57
I currently can't access the dataset, the iris dataset would be the same since it has both numeric and non numeric variables — GGA, Apr 15 '16 at 14:06

score 0 · Accepted Answer · answered Apr 15 '16 at 14:36

0

One way would be to loop over the column names:

nums <- sapply(db, is.numeric)
numsNames <- names(db)[nums]

sapply(numsNames, function(x) {
  hist(db[,x], xlab=x)
  lines(density(db[,x], na.rm = T))
})

answered Apr 15 '16 at 14:36

lmo

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score 0 · Answer 2 · answered Apr 16 '16 at 10:50

You could use mapply to take the data and other arguments to hist

num <- sapply(iris, is.numeric)
opar <- par(mfrow = c(2,2))
histDensity <- function(x, ...){
  hist(x = x, freq = FALSE, ...)
  lines(density(x, na.rm = TRUE))
}
mapply(histDensity, x = iris[, num], main = names(iris[, num]))
par(opar)

Alternatively, you could use ggplot

library(reshape2)
library(ggplot2)
iris2 <- melt(iris)
ggplot(iris2, aes(x = value, y = ..density..)) + 
  geom_histogram() +
  geom_density() +
  facet_wrap(~variable)

R sapply name to graph x axis

2 Answers2