CODEWITHSUNDEEP
r
showkey
showkey

Reputation: 348

How to write the proper regular expression to extract value from the string?

> str="  9.48  12.89 13.9    6.79   "
> strsplit(str,split="\\s+")
[[1]]
[1] ""      "9.48"  "12.89" "13.9"  "6.79" 

> unlist(strsplit(str,split="\\s+"))->y
> y[y!=""]
[1] "9.48"  "12.89" "13.9"  "6.79"

How can i get it by a single regular expression with strsplit , not to oparate it with y[y!=""]?

Upvotes: 1

Views: 76

Answers (2)

CHP
CHP

Reputation: 17189

If you want to extract just the numbers perhaps following regex would do.

regmatches(str, gregexpr("[0-9.]+", text = str))[[1]]
## [1] "9.48"  "12.89" "13.9"  "6.79"

To capture -ve numbers you can use following

str = "  9.48  12.89 13.9    --6.79   "
regmatches(str, gregexpr("\\-{0,1}[0-9.]+", text = str))[[1]]
## [1] "9.48"  "12.89" "13.9"  "-6.79"

Upvotes: 1

A5C1D2H2I1M1N2O1R2T1
A5C1D2H2I1M1N2O1R2T1

Reputation: 193517

I would just trim the string before splitting it:

strsplit(gsub("^\\s+|\\s+$", "", str), "\\s+")[[1]]
# [1] "9.48"  "12.89" "13.9"  "6.79"

Alternatively, it is pretty direct to use scan in this case:

scan(text=str)
# Read 4 items
# [1]  9.48 12.89 13.90  6.79

Upvotes: 2

Related Questions