Extracting string from "spssdata.GetFileHandles()" list (in R)

[Andy W]

This is more of an R question - but I ask here as it has to do with meta data retrieved from SPSS.

So I have a set of FILE HANDLES, and I want to extract the "save" FILE HANDLE and map the current R directory to that location. I'm confused how to extract the locations out of the list that R returns when I use the spssdata.GetFileHandles() function. Example syntax below:

****************************************************.
FILE HANDLE data /NAME = "H:\DATA FILES\KINGSTON\2014".
FILE HANDLE save /NAME = "data\AndyChartsGraphs".

BEGIN PROGRAM R.
handles <- spssdata.GetFileHandles()
handles

#handles[[2]][1] #this is how I thought you would extract the save handle
                 #it only returns - [1] "save" - though
END PROGRAM.
****************************************************.

Below is the subsequent output:

----------------------------------------------------------------------------
[[1]]
[1] "data"                           "H:\\DATA FILES\\KINGSTON\\2014" "windows-1252"
 
[[2]]
[1] "save"                                             "H:\\DATA FILES\\KINGSTON\\2014\\AndyChartsGraphs"
[3] "windows-1252"
----------------------------------------------------------------------------

Reading the R output is difficult, but you can see what I thought would be the code to extract the "H:\\DATA FILES\\KINGSTON\\2014\\AndyChartsGraphs" portion, but I was incorrect. Can any R guru's here tell me how to extract the relevant string so I can set my R working directory accordingly? Also the FILE HANDLE I will always want will be named "save" - but I may have more than 2 FILE HANDLES, so I presume just grabbing the string based on the index number of the list is not optimal, as its location may change if I add in more FILE HANDLES in different code or a later date.

[Andy W]

I should have been more patient - I see that R's print method led me slightly astray, I needed to use handles[[2]][2] instead of handles[[2]][1] (the print object was just not annotated with the index order. Still my question stands though how to figure out that I want [[2]] (because [[2]][1] == "save") and then extract [[2]][2] - if you can follow me with all those indices!

****************************************************.
FILE HANDLE data /NAME = "H:\DATA FILES\KINGSTON\2014".
FILE HANDLE save /NAME = "data\AndyChartsGraphs".

BEGIN PROGRAM R.
handles <- spssdata.GetFileHandles()
handles

x <- handles[[2]][2] #this is how I thought you would extract the save handle
                 #it only returns - [1] "save" - though
setwd(x)
getwd()
png(file="Test.png",height = 750, width = 750)
print(plot(0:10))
dev.off()
END PROGRAM.
****************************************************.

[Jon K Peck]

You could bracket this (even more) to death, but in the interest of vision health, try it like this
begin program r.
handles <- spssdata.GetFileHandles()

for (i in 1:length(handles)) {
    z = handles[i][[1]]
    if (z[[1]] == "save") {
        thepath = z[[2]]
    }
}
print(thepath)
end program.


Jon Peck (no "h") aka Kim
Senior Software Engineer, IBM
[hidden email]
phone: [phone]




From:        Andy W <[hidden email]>
To:        [hidden email],
Date:        02/25/2014 08:21 AM
Subject:        [SPSSX-L] Extracting string from "spssdata.GetFileHandles()" list              (in R)
Sent by:        "SPSSX(r) Discussion" <[hidden email]>

---

This is more of an R question - but I ask here as it has to do with meta data
retrieved from SPSS.

So I have a set of FILE HANDLES, and I want to extract the "save" FILE
HANDLE and map the current R directory to that location. I'm confused how to
extract the locations out of the list that R returns when I use the
spssdata.GetFileHandles() function. Example syntax below:

****************************************************.
FILE HANDLE data /NAME = "H:\DATA FILES\KINGSTON\2014".
FILE HANDLE save /NAME = "data\AndyChartsGraphs".

BEGIN PROGRAM R.
handles <- spssdata.GetFileHandles()
handles

#handles[[2]][1] #this is how I thought you would extract the save handle
                #it only returns - [1] "save" - though
END PROGRAM.
****************************************************.

Below is the subsequent output:

----------------------------------------------------------------------------
[[1]]
[1] "data"                           "H:\\DATA FILES\\KINGSTON\\2014"
"windows-1252"

[[2]]
[1] "save"                                             "H:\\DATA
FILES\\KINGSTON\\2014\\AndyChartsGraphs"
[3] "windows-1252"
----------------------------------------------------------------------------

Reading the R output is difficult, but you can see what I thought would be
the code to extract the "H:\\DATA FILES\\KINGSTON\\2014\\AndyChartsGraphs"
portion, but I was incorrect. Can any R guru's here tell me how to extract
the relevant string so I can set my R working directory accordingly? Also
the FILE HANDLE I will always want will be named "save" - but I may have
more than 2 FILE HANDLES, so I presume just grabbing the string based on the
index number of the list is not optimal, as its location may change if I add
in more FILE HANDLES in different code or a later date.



-----
Andy W
[hidden email]
http://andrewpwheeler.wordpress.com/
--
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[Albert-Jan Roskam]

I like to store all the handles in one object.

file handle tempdir /name = "%temp%".

* in R.
begin program r.
fh <- spssdata.GetFileHandles()
file_handles <- sapply(fh, function(x) x[2])
names(file_handles) <-  sapply(fh, function(x) x[1])
tempdir <- file_handles["tempdir"]
print(sprintf("tempdir in R: %s", tempdir))
end program.

* the equivalent in Python.
begin program python.
import spss, spssaux
file_handles = {f[0]: f[1] for f in spss.GetFileHandles()}
tempdir = file_handles["tempdir"]
print "(1) tempdir in Python", tempdir
print "(2) tempdir in Python", spssaux.FileHandles().resolve("tempdir")
end program.


Regards,

Albert-Jan



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a

fresh water system, and public health, what have the Romans ever done for us?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

--------------------------------------------
On Tue, 2/25/14, Andy W <[hidden email]> wrote:

 Subject: Re: [SPSSX-L] Extracting string from "spssdata.GetFileHandles()"              list (in R)
 To: [hidden email]
 Date: Tuesday, February 25, 2014, 4:31 PM

 I should have been more patient - I
 see that R's print method led me slightly
 astray, I needed to use handles[[2]][2] instead of
 handles[[2]][1] (the
 print object was just not annotated with the index order.
 Still my question
 stands though how to figure out that I want [[2]] (because
 [[2]][1] ==
 "save") and then extract [[2]][2] - if you can follow me
 with all those
 indices!

 ****************************************************.
 FILE HANDLE data /NAME = "H:\DATA FILES\KINGSTON\2014".
 FILE HANDLE save /NAME = "data\AndyChartsGraphs".

 BEGIN PROGRAM R.
 handles <- spssdata.GetFileHandles()
 handles

 x <- handles[[2]][2] #this is how I thought you would
 extract the save
 handle

    #it only returns - [1] "save" - though
 setwd(x)
 getwd()
 png(file="Test.png",height = 750, width = 750)
 print(plot(0:10))
 dev.off()
 END PROGRAM.
 ****************************************************.



 -----
 Andy W
 [hidden email]
 http://andrewpwheeler.wordpress.com/
 --
 View this message in context: http://spssx-discussion.1045642.n5.nabble.com/Extracting-string-from-spssdata-GetFileHandles-list-in-R-tp5724621p5724622.html
 Sent from the SPSSX Discussion mailing list archive at
 Nabble.com.

 =====================
 To manage your subscription to SPSSX-L, send a message to
 [hidden email]
 (not to SPSSX-L), with no body text except the
 command. To leave the list, send the command
 SIGNOFF SPSSX-L
 For a list of commands to manage subscriptions, send the
 command
 INFO REFCARD

=====================
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[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
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[Andy W]

Thank you Jon - exactly what I was looking for.

Albert-Jan - thanks for that example as well. Wrapping my head around the different R objects I find difficult (my googling to find similar examples was not being very productive either - list is a difficult search term). It took me a bit to figure out that "names(file_handles) <-  sapply(fh, function(x) x[1])" returns a vector with the index "name" labels as the original SPSS mapped string. If I had figured something out myself I would have probably tried to coerce it to a data frame (as I just tend to think in data frames) - but this is clearly a better format for the data to be in than a dataframe.

Thank you both again,
Andy