system() not accepting strings from cat()

Hi again R-ists,

How do you construct a string that you can pass to system()?

For instance. Say I do
system("echo Hello!")
Hello!

That works. Now the alternative: I need to construct the string like this
a <- "echo"
b <- "Hello!"
c <- "\n"
cat(a, b, c)
echo Hello!

Looks nice... but see what happens when I try to use it
system(cat(a, b, c))
echo Hello! 
Error in system(command, intern) : non-empty character argument expected

I have googled extensively in and out of r-lists but I can't find a solution.

Can anybody help?
try
?paste

baptiste

Hi again R-ists,

How do you construct a string that you can pass to system()?

For instance. Say I do

system("echo Hello!")
Hello!

That works. Now the alternative: I need to construct the string like  
this

a <- "echo"
b <- "Hello!"
c <- "\n"
cat(a, b, c)
echo Hello!

Looks nice... but see what happens when I try to use it

system(cat(a, b, c))
echo Hello!
Error in system(command, intern) : non-empty character argument  
expected

I have googled extensively in and out of r-lists but I can't find a  
solution.

Can anybody help?

______________________________________________
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.
_____________________________

Baptiste Augui?

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag
OH! The joy!

It worked like a sharm.

Thank you.

culpritNr1

try
?paste

baptiste

On 10 Mar 2009, at 20:01, ig2ar-saf1 at yahoo.co.uk wrote:

Hi again R-ists,

How do you construct a string that you can pass to system()?

For instance. Say I do

system("echo Hello!")
Hello!

That works. Now the alternative: I need to construct the string like  
this

a <- "echo"
b <- "Hello!"
c <- "\n"
cat(a, b, c)
echo Hello!

Looks nice... but see what happens when I try to use it

system(cat(a, b, c))
echo Hello!
Error in system(command, intern) : non-empty character argument  
expected

I have googled extensively in and out of r-lists but I can't find a  
solution.

Can anybody help?

______________________________________________
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.

_____________________________

Baptiste Augui?

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag

______________________________________________
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.

View this message in context: http://www.nabble.com/system%28%29-not-accepting-strings-from-cat%28%29-tp22442414p22442991.html
Sent from the R help mailing list archive at Nabble.com.
I meant charm, not sharm!

(how embarrasing...)
OH! The joy!

It worked like a sharm.

Thank you.

culpritNr1

baptiste auguie-2 wrote:

try
?paste

baptiste

On 10 Mar 2009, at 20:01, ig2ar-saf1 at yahoo.co.uk wrote:

Hi again R-ists,

How do you construct a string that you can pass to system()?

For instance. Say I do

system("echo Hello!")
Hello!

That works. Now the alternative: I need to construct the string like  
this

a <- "echo"
b <- "Hello!"
c <- "\n"
cat(a, b, c)
echo Hello!

Looks nice... but see what happens when I try to use it

system(cat(a, b, c))
echo Hello!
Error in system(command, intern) : non-empty character argument  
expected

I have googled extensively in and out of r-lists but I can't find a  
solution.

Can anybody help?

______________________________________________
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.

_____________________________

Baptiste Augui?

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag

______________________________________________
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.

View this message in context: http://www.nabble.com/system%28%29-not-accepting-strings-from-cat%28%29-tp22442414p22443015.html
Sent from the R help mailing list archive at Nabble.com.
embarrasSing, not embarrasing.

You see how I became culpritNr1?
I meant charm, not sharm!

(how embarrasing...)

culpritNr1 wrote:
OH! The joy!

It worked like a sharm.

Thank you.

culpritNr1

baptiste auguie-2 wrote:

try
?paste

baptiste

On 10 Mar 2009, at 20:01, ig2ar-saf1 at yahoo.co.uk wrote:

Hi again R-ists,

How do you construct a string that you can pass to system()?

For instance. Say I do

system("echo Hello!")
Hello!

That works. Now the alternative: I need to construct the string like  
this

a <- "echo"
b <- "Hello!"
c <- "\n"
cat(a, b, c)
echo Hello!

Looks nice... but see what happens when I try to use it

system(cat(a, b, c))
echo Hello!
Error in system(command, intern) : non-empty character argument  
expected

I have googled extensively in and out of r-lists but I can't find a  
solution.

Can anybody help?

______________________________________________
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.

_____________________________

Baptiste Augui?

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag

______________________________________________
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.

View this message in context: http://www.nabble.com/system%28%29-not-accepting-strings-from-cat%28%29-tp22442414p22443051.html
Sent from the R help mailing list archive at Nabble.com.

I meant charm, not sharm!

(how embarrasing...)
If you're embarrassed by ***that*** you need to watch more Monty  
Python! :-)

	cheers,

		Rolf Turner

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