Entire Results from R

[msanchez78]

seeking the wisdom of the perl monks ...

within R i submit this code:

> data <- c("2016-03-15 13","2016-03-16 23","2016-03-17 06","2016-03-1
+8 15","2016-03-19 08","2016-03-20 21")
> datevec <- strptime(data,"%Y-%m-%d %H")
> difftime(datevec[-length(datevec)],datevec[-1],units="hours")

which correctly produces this output:
Time differences in hours
1 -34 -7 -33 -17 -37

notice the two lines. now, in perl i have this code:

$R->set( 'data', "2016-03-15 13","2016-03-16 23","2016-03-17 06","2016
+-03-18 15","2016-03-19 08","2016-03-20 21" );
$R->run( q`datevec <- strptime(data,"%Y-%m-%d %H")` );
$R->run( q`xx <- difftime(datevec[-length(datevec)],datevec[-1],units=
+"hours")` );
@Rres = $R->get('xx');
print Dumper(\@Rres);

which correctly produces this result:

$VAR1 = [
          [
            'Time',
            'difference',
            'of',
            'hours'
          ]
        ];

the problem is that no matter what i do i cannot get to the second output line from R ... the line 1 -34 -7 -33 -17 -37

any suggestion on how i can get to the second (and in many cases n-number) of subsequent output lines from R? thanks!

[Veltro]

Can you try to print the raw result? Maybe this will help to see what is wrong.

   my $tmp_str = $R->run(qq`print($varname)`);
   print $tmp_str . "\n" ;

I got the previous line from the 'get' method of the module Statistics::R which I assume you are using. The 'get' method is doing a whole bunch of other stuff (which may cause the problem), so this line might show the entire result. Another small thing is that you are using @Rres = $R->get('xx'); and the method is returning a array reference. Although it is not entirely incorrect I do suggest using my $Rres = $R->get('xx'); print Dumper($Rres); instead

Further I don't know much about R

edit: Oh, and $varname should be 'datevec' or 'xx' or in this case of course.

[msanchez78]

hi ... thank you for your prompt reply. i tried

   my $tmp_str = $R->run(qq`print($varname)`);
   print $tmp_str . "\n" ;

the result is the same --- the first line only:

Time difference of hours

yikes!

[Your Mother]

I would go in and manually edit this line to 1–

use constant DEBUG      => 0;                     # debugging messages

And see what you get.

[haukex]

Your use of $R->set() is incorrect: to set multiple values, you have to pass an arrayref: $R->set( 'data', ["2016-03-15 13","2016-03-16 23","2016-03-17 06","2016-03-18 15","2016-03-19 08","2016-03-20 21"] ); Then the code works for me.

[kevbot]

++haukex I put together a short script to confirm that your solution works (I was curious about Statistics::R since I had not used it before). This code,

#!/usr/bin/env perl

use Statistics::R;
use Data::Dumper;

# Create a communication bridge with R and start R
my $R = Statistics::R->new();

$R->set(
    'data',
    [
        "2016-03-15 13",
        "2016-03-16 23",
        "2016-03-17 06",
        "2016-03-18 15",
        "2016-03-19 08",
        "2016-03-20 21"
    ]
);

$R->run( q`datevec <- strptime(data,"%Y-%m-%d %H")` );
$R->run( q`xx <- difftime(datevec[-length(datevec)],datevec[-1],units=
+"hours")` );
@Rres = $R->get('xx');

print Dumper(\@Rres);

exit;

Gives this output,

$VAR1 = [
          [
            '[1]',
            '-34',
            '-7',
            '-33',
            '-17',
            '-37'
          ]
        ];

[haukex]

Thanks for the example! I also submitted a pull request that adds a "too many arguments" error to ->set.