Skip to content

removing part of a string

4 messages · Vito M. R. Muggeo, Ulrik Stervbo, Rui Barradas

Vito M. R. Muggeo
# 
dear all,
I am stuck on the following problem. Give a string like

ss1<- "z:f(5, a=3, b=4, c='1:4', d=2)"

or

ss2<- "f(5, a=3, b=4, c=\"1:4\", d=2)*z"

I would like to remove all entries within parentheses.. Namely, I aim to 
obtain respectively

"z:f()" or "f()*z"

I played with sub() and gsub() but without success..
Thank you very much for your time,

best,
vito
Rui Barradas
# 
Hello,

Try this.


ss1 <- "z:f(5, a=3, b=4, c='1:4', d=2)"
ss2 <- "f(5, a=3, b=4, c=\"1:4\", d=2)*z"

fun <- function(s) sub("(\\().*(\\))", "\\1\\2", s)

fun(ss1)
#[1] "z:f()"

fun(ss2)
#[1] "f()*z"


Hope this helps,

Rui Barradas
On 5/21/2018 2:33 PM, Vito M. R. Muggeo wrote:
Ulrik Stervbo
# 
I would use

sub("\\(.*\\)", "()", s)

It is essentially the same as Rui's suggestion, but I find the purpose to
be more clear. It might also be a little more efficient.

HTH
Ulrik
On Mon, 21 May 2018, 15:38 Rui Barradas, <ruipbarradas at sapo.pt> wrote:

            

      
      
      
    

        

      
      
    

        

  
  


  


      

    

    

      
      

        


  

        

      Rui Barradas
    

    

      
      #
    

  


  

      
Hello,

Ulrik's way is simpler therefore better. I would use it, not mine.

As for an explanation of mine, here it goes.

1) Parenthesis are meta-characters and must be escaped if you want to 
match them:

\\(  and  \\)

2) You want to keep them so I used groups, i.e., put what you want 
between parenthesis (these serve a different purpose, they will not be 
matched).

(\\()  and (\\))  are group \1 and group \2

3) remove everything between the two groups:

.*

4) combine all:

(\\().*(\\))  is the pattern to match

The replacement is \\1\\2

Ulrik's pattern is simpler, no groups, just \\( and \\) with .* between 
them, replaced by ()

Hope this helps,

Rui Barradas

        
On 5/21/2018 3:00 PM, Ulrik Stervbo wrote: