CODEWITHSUNDEEP
regexr
jay_phate
jay_phate

Reputation: 439

Extracting patterns from text in R

My data is like:

t <- "The data is like hi hi hi hi  and hi hi end"

and my regular expression is:

grammer <- "[[:space:]]*(hi)+[[:space:]]"

After executing below two lines:

res <- gregexpr(grammer, t)
regmatches(t, res)

I got output:

 [[1]]
 [1] " hi " "hi "  "hi "  "hi "  " hi " "hi "

however, I want something like: " hi hi hi hi " and " hi hi "

Upvotes: 7

Views: 118

Answers (1)

Avinash Raj
Avinash Raj

Reputation: 174706

You could do like this,

> t<-"The data is like hi hi hi hi  and hi hi end"
> grammer<-"[[:space:]]*(hi[[:space:]])+[[:space:]]*"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi  " " hi hi "

OR

> grammer<-"[[:space:]]*(hi[[:space:]])+"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi " " hi hi "

OR

> t <- "The data is like hi hi hi hi and hi hi end hi"
> grammer<-"[[:space:]]*(hi\\>[[:space:]]?)+"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi " " hi hi "       " hi"

Without leading or following spaces.

> t <- "The data is like hi hi hi hi and hi hi end hi"
> grammer<-"hi\\>([[:space:]]hi)*"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] "hi hi hi hi" "hi hi"       "hi"

Explanation:

  • [[:space:]]* Matches a space character zero or more times.
  • (hi[[:space:]])+ Matches the string hi and the following space one or more times.

Upvotes: 4

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