[R] Please help -- Cbind data frames within LIST() in R

[Sunny Singha]

Thanks Petr,
I'm going through the link that you have provided. Merge won't be useful in
my case. Let me give the complete picture of what I'm trying to achieve.

I'm extracting data from fb pages. I have the data frame 'pages_df' which
has all the details of the fb pages. 'Page_id' is the important column in
it to get all the posts from that page.

I have created below function to which page_id is passed and data frame is
created separately for 'posts.csv', 'comments.csv', 'likescsv'.
Ideally this is not what I want as the final output. I want to modify this
function so that it outputs single flat file where columns of
each posts, comments and likes are cbinded.

# Function to scrap facebook pages' posts, comments and likes
page_data_extract <- function(pg_id){
  cat('Extracting list of posts from page', pg_id, '\n')
  page <- getPage(pg_id, token=fb_oauth, since='2016/03/01') # This
function extracts posts metadata from page_id argument specified.

  # Loop to information of the post.
  for(i in 1:nrow(page)){
    path_dat <- <custom_path>
    cat('\nScrapping post \n',page$id[i])

    posts <- getPost(page$id[i], n=100, token =fb_oauth)
    time <- format(Sys.time(), '%b_%d_%Y')
    for(j in 1:length(posts)){
      myfile <- file.path(path_data, paste0(names(posts[j]), time, '_', i,
'.csv'))
      write.csv(posts[[j]], file=myfile, row.names = F)
    }
  }
}

Here I call the above function:
 # Call page_data_extract() function for each pages found to gather posts,
comments & Likes
for(i in 1:nrow(pages_df)){
    e_catch <- try(page_data_extract(pages_df$id[i]))
    if(isTRUE(all.equal(class(e_catch), 'try-error'))){
      cat('No public posts were found for ==
',pages_df$name[i],'(',pages_df$id[i],')\n\n')
    }
}

Regards,
Sunny

On Mon, Mar 14, 2016 at 1:19 PM, PIKAL Petr <petr.pikal at precheza.cz> wrote:

> Hi
>
> There are several options e.g.
>
>
> http://stackoverflow.com/questions/6988184/combining-two-data-frames-of-different-lengths
>
> http://stackoverflow.com/questions/7196450/create-a-data-frame-of-unequal-lengths
>
> but maybe you want to do actually merging
>
> see
>
> ?merge
>
> Cheers
> Petr
>
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Sunny
> > Singha
> > Sent: Monday, March 14, 2016 8:16 AM
> > To: r-help
> > Subject: [R] Please help -- Cbind data frames within LIST() in R
> >
> > Hi,
> > Please help and guide. I want to cbind dataframes within the list
> > object:
> > List object 'post_data' contains below sampled data frames:
> >
> > post_data
> > $posts
> >       from_id user_name post_msg
> >
> > $comm
> >        comm_id from_id message
> >
> > $Likes
> >        username like_id
> >
> >
> > *Note: The columns in each data frame are of unequal length. hence,
> > missing values will be filled with 'NA' after combining* Regards, Sunny
> >
> >       [[alternative HTML version deleted]]
> >
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> > and provide commented, minimal, self-contained, reproducible code.
>
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