CODEWITHSUNDEEP
r
user1471980
user1471980

Reputation: 10626

regex out a text from a line in R

I have line like this:

x<-c("System configuration: lcpu=96 mem=196608MB ent=16.00")

I need to the the value equal to ent and store it in val object in R

I am doing this not not seem to be working. Any ideas?

 val<-x[grep("[0-9]$", x)]

Upvotes: 1

Views: 90

Answers (3)

Jim
Jim

Reputation: 4767

Using rex may make this type of task a little simpler.

Note this solution correctly includes . in the capture, as does G. Grothendieck's answer.

x <- c("System configuration: lcpu=96 mem=196608MB ent=16.00")

library(rex)
val <- as.numeric(
  re_matches(x,
    rex("ent=",
      capture(name = "ent", some_of(digit, "."))
      )
    )$ent
  )
#>[1] 16

Upvotes: 0

G. Grothendieck
G. Grothendieck

Reputation: 269481

If ent is always at the end then:

sub(".*ent=", "", x)

If not try strapplyc in the gsubfn package which returns only the portion of the regular expression within parentheses:

library(gsubfn)
strapplyc(x, "ent=([.0-9]+)", simplify = TRUE)

Also it could be converted to numeric at the same time using strapply :

strapply(x, "ent=([.0-9]+)", as.numeric, simplify = TRUE)

Upvotes: 3

Justin
Justin

Reputation: 43255

use sub:

val <- sub('^.* ent=([[:digit:]]+)', '\\1', x)

Upvotes: 4

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