Question

I am working on saving twitter search results into a database (SQL Server) and am getting an error when I pull the search results from twitteR.

If I execute:

library(twitteR)
puppy <- as.data.frame(searchTwitter("puppy", session=getCurlHandle(),num=100))

I get an error of:

Error in as.data.frame.default(x[[i]], optional = TRUE) : 
  cannot coerce class structure("status", package = "twitteR") into a data.frame

This is important because in order to use RODBC to add this to a table using sqlSave it needs to be a data.frame. At least that’s the error message I got:

Error in sqlSave(localSQLServer, puppy, tablename = "puppy_staging",  : 
  should be a data frame

So does anyone have any suggestions on how to coerce the list to a data.frame or how I can load the list through RODBC?

My final goal is to have a table that mirrors the structure of values returned by searchTwitter. Here is an example of what I am trying to retrieve and load:

library(twitteR)
puppy <- searchTwitter("puppy", session=getCurlHandle(),num=2)
str(puppy)

List of 2
 $ :Formal class 'status' [package "twitteR"] with 10 slots
  .. ..@ text        : chr "beautifull and  kc reg Beagle Mix for rehomes: This little puppy is looking for a new loving family wh... http://bit.ly/9stN7V "| __truncated__
  .. ..@ favorited   : logi FALSE
  .. ..@ replyToSN   : chr(0) 
  .. ..@ created     : chr "Wed, 16 Jun 2010 19:04:03 +0000"
  .. ..@ truncated   : logi FALSE
  .. ..@ replyToSID  : num(0) 
  .. ..@ id          : num 1.63e+10
  .. ..@ replyToUID  : num(0) 
  .. ..@ statusSource: chr "&lt;a href=&quot;http://twitterfeed.com&quot; rel=&quot;nofollow&quot;&gt;twitterfeed&lt;/a&gt;"
  .. ..@ screenName  : chr "puppy_ads"
 $ :Formal class 'status' [package "twitteR"] with 10 slots
  .. ..@ text        : chr "the cutest puppy followed me on my walk, my grandma won't let me keep it. taking it to the pound sadface"
  .. ..@ favorited   : logi FALSE
  .. ..@ replyToSN   : chr(0) 
  .. ..@ created     : chr "Wed, 16 Jun 2010 19:04:01 +0000"
  .. ..@ truncated   : logi FALSE
  .. ..@ replyToSID  : num(0) 
  .. ..@ id          : num 1.63e+10
  .. ..@ replyToUID  : num(0) 
  .. ..@ statusSource: chr "&lt;a href=&quot;http://blackberry.com/twitter&quot; rel=&quot;nofollow&quot;&gt;Twitter for BlackBerry®&lt;/a&gt;"
  .. ..@ screenName  : chr "iamsweaters"

So I think the data.frame of puppy should have column names like:

- text
- favorited
- replytoSN
- created
- truncated
- replytoSID
- id
- replytoUID
- statusSource
- screenName

Answer 1

Try this:

ldply(searchTwitter("#rstats", n=100), text)

twitteR returns an S4 class, so you need to either use one of its helper functions, or deal directly with its slots. You can see the slots by using unclass(), for instance:

unclass(searchTwitter("#rstats", n=100)[[1]])

These slots can be accessed directly as I do above by using the related functions (from the twitteR help: ?statusSource):

 text Returns the text of the status
 favorited Returns the favorited information for the status
 replyToSN Returns the replyToSN slot for this status
 created Retrieves the creation time of this status
 truncated Returns the truncated information for this status
 replyToSID Returns the replyToSID slot for this status
 id Returns the id of this status
 replyToUID Returns the replyToUID slot for this status
 statusSource Returns the status source for this status

As I mentioned, it’s my understanding that you will have to specify each of these fields yourself in the output. Here’s an example using two of the fields:

> head(ldply(searchTwitter("#rstats", n=100), 
        function(x) data.frame(text=text(x), favorited=favorited(x))))
                                                                                                                                          text
1                                                     @statalgo how does that actually work? does it share mem between #rstats and postgresql?
2                                   @jaredlander Have you looked at PL/R? You can call #rstats from PostgreSQL: http://www.joeconway.com/plr/.
3   @CMastication I was hoping for a cool way to keep data in a DB and run the normal #rstats off that. Maybe a translator from R to SQL code.
4                     The distribution of online data usage: AT&T has recently announced it will no longer http://goo.gl/fb/eTywd #rstat
5 @jaredlander not that I know of. Closest is sqldf package which allows #rstats and sqlite to share mem so transferring from DB to df is fast
6 @CMastication Can #rstats run on data in a DB?Not loading it in2 a dataframe or running SQL cmds but treating the DB as if it wr a dataframe
  favorited
1     FALSE
2     FALSE
3     FALSE
4     FALSE
5     FALSE
6     FALSE

You could turn this into a function if you intend on doing it frequently.