R help - Jun 2015 - Passing strings with spaces to Python using system2 splits string at whitespace

Hi all,

I am trying to pass arguments to a python script using R, but am running into a
problem with the string being split on the white spaces. Investigation on the
python end suggests that it is happening upstream from python, because other
shells such as bash have generated similar errors.

Here is example code.

R script:

test = "./Example.py"
string1 = "ThisWorks"
string2 = "This doesn't"

system2('python',args = c(as.character(test),as.character(string1))) ##
This works
system2('python',args = c(as.character(test),as.character(string2))) ##
This doesn't

Python script:

from sys import argv
script, string = argv
print script
print string

What happens is that string 2 is splits into "This" and
"doesn't". Does anyone know how to resolve this issue? Of course I
can remove the white spaces, but that may be somewhat inconvenient.

Thanks for any help.


Wade



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On Jun 4, 2015, at 8:47 AM, Wall, Wade A ERDC-RDE-CERL-IL <Wade.A.Wall at
usace.army.mil> wrote:
> 
> Hi all,
> 
> I am trying to pass arguments to a python script using R, but am running
into a problem with the string being split on the white spaces. Investigation on
the python end suggests that it is happening upstream from python, because other
shells such as bash have generated similar errors.
> 
> Here is example code.
> 
> R script:
> 
> test = "./Example.py"
> string1 = "ThisWorks"
> string2 = "This doesn't"
> 
> system2('python',args =
c(as.character(test),as.character(string1))) ## This works
> system2('python',args =
c(as.character(test),as.character(string2))) ## This doesn't
> 
> Python script:
> 
> from sys import argv
> script, string = argv
> print script
> print string
> 
> What happens is that string 2 is splits into "This" and
"doesn't". Does anyone know how to resolve this issue? Of course I
can remove the white spaces, but that may be somewhat inconvenient.
> 
> Thanks for any help.
> 
> 
> Wade

See ?shQuote
> shQuote(string2)
[1] ?\"This doesn?t\""


Regards,

Marc Schwartz

On Thu, Jun 4, 2015 at 8:47 AM, Wall, Wade A ERDC-RDE-CERL-IL <
Wade.A.Wall at usace.army.mil> wrote:
> Hi all,
>
> I am trying to pass arguments to a python script using R, but am running
> into a problem with the string being split on the white spaces.
> Investigation on the python end suggests that it is happening upstream from
> python, because other shells such as bash have generated similar errors.
>
> Here is example code.
>
> R script:
>
> test = "./Example.py"
> string1 = "ThisWorks"
> string2 = "This doesn't"
>
> system2('python',args =
c(as.character(test),as.character(string1))) ##
> This works
> system2('python',args =
c(as.character(test),as.character(string2))) ##
> This doesn't
>
?use shQuote, like:

system2('python',args=shQuote(c(as.character(test),as.character(string2))))?

> Python script:
>
> from sys import argv
> script, string = argv
> print script
> print string
>
> What happens is that string 2 is splits into "This" and
"doesn't". Does
> anyone know how to resolve this issue? Of course I can remove the white
> spaces, but that may be somewhat inconvenient.
>
> Thanks for any help.
>
> Wade
>
>         [[alternative HTML version deleted]]
>
?Please don't use HTML email. It often causes messages to be unreadable?,
although not in this particular case.


>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>


-- 
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Ask him to dribble a football.

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