CODEWITHSUNDEEP
rvector
heisenberg7584
heisenberg7584

Reputation: 740

Remove non numeric values from vector in r

Is there a simple way to remove all non numeric values from a vector in r? Suppose we have:

vec <- c(1, 2, T, 'x', 'abc', '6', 7, F, F, 10)

I would like to receive:

c(1, 2, 7, 10)

Upvotes: 0

Views: 4134

Answers (4)

ThetaFC
ThetaFC

Reputation: 670

c is a function that returns a vector where "all arguments are coerced to a common type...The output type is determined from the highest type of the components in the hierarchy NULL < raw < logical < integer < double < complex < character < list < expression."

Thus, you need a container where you can have mixed data types to test which ones are numeric. A list gives you this. This approach leaves out the '6':

vec_list <- list(1, 2, T, 'x', 'abc', '6', 7, F, F, 10)
unlist(vec_list[sapply(vec_list, function(x) if(class(x)=='numeric') {T} else {F})])

[1] 1 2 7 10

Upvotes: 2

ThomasIsCoding
ThomasIsCoding

Reputation: 101733

A simple solution is to use Filter over vec <- list(1, 2, T, 'x', 'abc', '6', 7, F, F, 10), i.e., 

> unlist(Filter(is.numeric,vec))
[1]  1  2  7 10

Upvotes: 1

IRTFM
IRTFM

Reputation: 263362

Techically the term vector includes lists that do not have attributes other than names, so here is a vector built with list rather than with c.

vec <- list(1, 2, T, 'x', 'abc', '6', 7, F, F, 10)

So that can be tested for "numericy"

vec[sapply(vec, is.numeric)]
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 7

[[4]]
[1] 10

Upvotes: 0

ClancyStats
ClancyStats

Reputation: 1231

You can use regex to look for elements that only contain the digits 0-9 along with periods and return them. The ^ matches the start of a character and $ matches the end so it will filter out any element which has both letters and numbers.

as.numeric(grep('^-?[0-9.]+$', vec, val = T))

Upvotes: 2

Related Questions