R help - Mar 2010 - remove substring from each string vector component

Hi all,

I have a string vector like that: x=c("1\t\t", "2",
"3\t\t\t")
I need to remove all the occurrences of "\t", in order to obtain: x =
"1"
"2"   "3"

I'm trying to use the function substring2, and it works for each component,
for example:
substring2(x[1], "\t") =""
gives x = "1"   "2"   " 3\t\t\t"

I'd like to apply this function to each component and I tried the following:

myfun = function(x, i) {
  substring2(x[i], "\t") = ""
}

lapply(x, myfun)

which gives x="" "" ""

I know that I'm wrong somewhere using lapply, but I can't fix it.

Thanks in advance,
Arnaud Chozo

	[[alternative HTML version deleted]]

Hi!
It's just this easy:

x=gsub("\t","",x)

For more complex things, it's worth learning some regular expressions
syntax.
Miguel


On Tue, Mar 16, 2010 at 2:50 PM, arnaud chozo
<arnaud.chozo@gmail.com>wrote:
> Hi all,
>
> I have a string vector like that: x=c("1\t\t", "2",
"3\t\t\t")
> I need to remove all the occurrences of "\t", in order to obtain:
x = "1"
> "2"   "3"
>
> I'm trying to use the function substring2, and it works for each
component,
> for example:
> substring2(x[1], "\t") =""
> gives x = "1"   "2"   " 3\t\t\t"
>
> I'd like to apply this function to each component and I tried the
> following:
>
> myfun = function(x, i) {
>  substring2(x[i], "\t") = ""
> }
>
> lapply(x, myfun)
>
> which gives x="" "" ""
>
> I know that I'm wrong somewhere using lapply, but I can't fix it.
>
> Thanks in advance,
> Arnaud Chozo
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

On Mar 16, 2010, at 9:50 AM, arnaud chozo wrote:
> Hi all,
> 
> I have a string vector like that: x=c("1\t\t", "2",
"3\t\t\t")
> I need to remove all the occurrences of "\t", in order to obtain:
x = "1"
> "2"   "3"
> 
> I'm trying to use the function substring2, and it works for each
component,
> for example:
> substring2(x[1], "\t") =""
> gives x = "1"   "2"   " 3\t\t\t"
> 
> I'd like to apply this function to each component and I tried the
following:
> 
> myfun = function(x, i) {
>  substring2(x[i], "\t") = ""
> }
> 
> lapply(x, myfun)
> 
> which gives x="" "" ""
> 
> I know that I'm wrong somewhere using lapply, but I can't fix it.
> 
> Thanks in advance,
> Arnaud Chozo

This is a place to use regular expressions with gsub():

x <- c("1\t\t", "2", "3\t\t\t")
> gsub("\\t", "", x)
[1] "1" "2" "3"

See ?regex and ?gsub

Note that you have to double the backslashes in the regex.

HTH,

Marc Schwartz

Hi Arnaud,
how about this:

x=c("1\t\t", "2", "3\t\t\t")

gsub("\t","",x)

hth.

arnaud chozo schrieb:
> Hi all,
>
> I have a string vector like that: x=c("1\t\t", "2",
"3\t\t\t")
> I need to remove all the occurrences of "\t", in order to obtain:
x = "1"
> "2"   "3"
>
> I'm trying to use the function substring2, and it works for each
component,
> for example:
> substring2(x[1], "\t") =""
> gives x = "1"   "2"   " 3\t\t\t"
>
> I'd like to apply this function to each component and I tried the
following:
>
> myfun = function(x, i) {
>   substring2(x[i], "\t") = ""
> }
>
> lapply(x, myfun)
>
> which gives x="" "" ""
>
> I know that I'm wrong somewhere using lapply, but I can't fix it.
>
> Thanks in advance,
> Arnaud Chozo
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>   
-- 
Eik Vettorazzi
Institut f?r Medizinische Biometrie und Epidemiologie
Universit?tsklinikum Hamburg-Eppendorf

Martinistr. 52
20246 Hamburg

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