R help - Aug 2011 - Using get() or similar function to access more than one element in a vector

Dear R-users,

I've written a script that produces a frequency table for a group of
texts. The table has a total frequency for each word type and
individual frequency counts for each of the files. (I have not
included the code for creating the column headers.) Below is a sample:

Word  Total 	01.txt	02.txt	03.txt	04.txt	05.txt
the	22442	2667	3651	1579	2132	3097
I	18377	3407	  454	  824	  449	3746
and	15521	2377	2174	  891	1006	2450
to	13598	1716	1395	  905	1021	1983
of	12834	1647	1557	  941	1127	1887
it	12440	2160	  916	  497	  493	2449
you	12036	2283	  356	  293	  106	2435

I've encountered two problems when I try to construct and save the file.

The "combined.sorted.freq.list" is a named integer vector in which the
integers are the total frequency counts for each word. The names are
the words. For each of the individual lists I've created frequency
lists that are sorted in the order of the combined list. (NAs have
been replaced with "0"). These are called "combined." plus
the number
of the file.
If I were to write the line to save the file manually, it would look like this:

combined.table<-paste(names(combined.sorted.freq.list),
combined.sorted.freq.list, combined.01, combined.02, combined.03,
combined.04, combined.05, combined.06, combined.07, combined.08,
combined.09, combined.10, combined.11, combined.12, sep="\t")
#creates a table with columns for the combined and all of the
component lists

However, each time I run the script, there may be a differing number
of text files. I created a list of the individual frequency counts
called "combined.file.list"

combined.file.count<-1:length(selected.files) #counts number of files
originally selected
combined.file.list<-paste("combined", combined.file.count,
sep=".")
#creates the file names for the combined lists by catenating
"combined" with each file number separated by a period by recycled the
string "combined for each number

I then tried to include it as one of the elements to be pasted by using get().

combined.table<-paste(names(combined.sorted.freq.list),
combined.sorted.freq.list, get(combined.file.list[]), sep="\t")
#intended to create a table with columns for the combined and all of
the component lists

Unfortunately, the get() function only gets the first component list
since get() can apparently only access one object.

This results in a table with only the total frequency and the amount
of the first text:

Word  Total	01.txt
the	22442	2667
I	18377	3407
and	15521	2377
to	13598	1716
of	12834	1647
it	12440	2160
you	12036	2283

If I try to construct the file "piece by piece" as they are created, I
get an error message that a vector of more than 1.3 Gb cannot be
created. Does anyone know how I could use get() or some other method
to access all of the files named in a vector?

Many thank for any help you can offer!

Joseph

Hi Joseph,

Without a reproducible example, you probably will not get the precise
code for a solution but look at ?list

Rather than doing what you are doing now, put everything into a list,
and then you will not need to use get() at all.  You will just work
with the whole list.  It can take a bit to get to get used to working
that way, but it is worth it.

Cheers,

Josh

On Sat, Aug 13, 2011 at 9:34 PM, Joseph Sorell <josephsorell at gmail.com>
wrote:
> Dear R-users,
>
> I've written a script that produces a frequency table for a group of
> texts. The table has a total frequency for each word type and
> individual frequency counts for each of the files. (I have not
> included the code for creating the column headers.) Below is a sample:
>
> Word ?Total ? ? 01.txt ?02.txt ?03.txt ?04.txt ?05.txt
> the ? ? 22442 ? 2667 ? ?3651 ? ?1579 ? ?2132 ? ?3097
> I ? ? ? 18377 ? 3407 ? ? ?454 ? ? 824 ? ? 449 ? 3746
> and ? ? 15521 ? 2377 ? ?2174 ? ? ?891 ? 1006 ? ?2450
> to ? ? ?13598 ? 1716 ? ?1395 ? ? ?905 ? 1021 ? ?1983
> of ? ? ?12834 ? 1647 ? ?1557 ? ? ?941 ? 1127 ? ?1887
> it ? ? ?12440 ? 2160 ? ? ?916 ? ? 497 ? ? 493 ? 2449
> you ? ? 12036 ? 2283 ? ? ?356 ? ? 293 ? ? 106 ? 2435
>
> I've encountered two problems when I try to construct and save the
file.
>
> The "combined.sorted.freq.list" is a named integer vector in
which the
> integers are the total frequency counts for each word. The names are
> the words. For each of the individual lists I've created frequency
> lists that are sorted in the order of the combined list. (NAs have
> been replaced with "0"). These are called "combined."
plus the number
> of the file.
> If I were to write the line to save the file manually, it would look like
this:
>
> combined.table<-paste(names(combined.sorted.freq.list),
> combined.sorted.freq.list, combined.01, combined.02, combined.03,
> combined.04, combined.05, combined.06, combined.07, combined.08,
> combined.09, combined.10, combined.11, combined.12, sep="\t")
> #creates a table with columns for the combined and all of the
> component lists
>
> However, each time I run the script, there may be a differing number
> of text files. I created a list of the individual frequency counts
> called "combined.file.list"
>
> combined.file.count<-1:length(selected.files) #counts number of files
> originally selected
> combined.file.list<-paste("combined", combined.file.count,
sep=".")
> #creates the file names for the combined lists by catenating
> "combined" with each file number separated by a period by
recycled the
> string "combined for each number
>
> I then tried to include it as one of the elements to be pasted by using
get().
>
> combined.table<-paste(names(combined.sorted.freq.list),
> combined.sorted.freq.list, get(combined.file.list[]), sep="\t")
> #intended to create a table with columns for the combined and all of
> the component lists
>
> Unfortunately, the get() function only gets the first component list
> since get() can apparently only access one object.
>
> This results in a table with only the total frequency and the amount
> of the first text:
>
> Word ?Total ? ? 01.txt
> the ? ? 22442 ? 2667
> I ? ? ? 18377 ? 3407
> and ? ? 15521 ? 2377
> to ? ? ?13598 ? 1716
> of ? ? ?12834 ? 1647
> it ? ? ?12440 ? 2160
> you ? ? 12036 ? 2283
>
> If I try to construct the file "piece by piece" as they are
created, I
> get an error message that a vector of more than 1.3 Gb cannot be
> created. Does anyone know how I could use get() or some other method
> to access all of the files named in a vector?
>
> Many thank for any help you can offer!
>
> Joseph
>
> ______________________________________________
> 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.
>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
Programmer Analyst II, ATS Statistical Consulting Group
University of California, Los Angeles
https://joshuawiley.com/