title: R: attempt to use zero-length variable name in filter.data.frame
body: <p>I'm not an R expert at all and am getting this error:</p>
  <blockquote>
  <p>Error in initialize(...) : attempt to use zero-length variable name
  Calls: %&gt;% ... filter.data.frame -&gt; filter_rows -&gt;  -&gt; initialize -&gt; .Call</p>
  </blockquote>
  <p>With logs, I've narrowed it down to this line of code:</p>
  <pre><code>qb_stats_all &lt;- subset(qb_stats_all, select = -c(num)) %&gt;% filter(player != 'Player')
  </code></pre>
  <p>And here is the full code before that:</p>
  <pre><code>library(data.table)
  library(dplyr)
  library(ggplot2)
  library(gtools)
  library(htmltab)
  library(jsonlite)
  library(stringr)
  library(XML)
  
  
  # Set earliest quarterback draft year
  beginning_qb_year &lt;- 1985
  
  
  # Set most recent quarterback draft year
  ending_qb_year &lt;- 2020
  
  
  # Scrape NFL quarterback career data
  url_start &lt;- paste0('https://www.pro-football-reference.com/play-index/psl_finder.cgi?request=1&amp;match=combined&amp;year_min=', beginning_qb_year, '&amp;year_max=2020&amp;season_start=1&amp;season_end=-1&amp;pos%5B%5D=qb&amp;draft_year_min=1936&amp;draft_year_max=2020&amp;draft_slot_min=1&amp;draft_slot_max=500&amp;draft_pick_in_round=pick_overall&amp;conference=any&amp;draft_pos%5B%5D=qb&amp;draft_pos%5B%5D=rb&amp;draft_pos%5B%5D=wr&amp;draft_pos%5B%5D=te&amp;draft_pos%5B%5D=e&amp;draft_pos%5B%5D=t&amp;draft_pos%5B%5D=g&amp;draft_pos%5B%5D=c&amp;draft_pos%5B%5D=ol&amp;draft_pos%5B%5D=dt&amp;draft_pos%5B%5D=de&amp;draft_pos%5B%5D=dl&amp;draft_pos%5B%5D=ilb&amp;draft_pos%5B%5D=olb&amp;draft_pos%5B%5D=lb&amp;draft_pos%5B%5D=cb&amp;draft_pos%5B%5D=s&amp;draft_pos%5B%5D=db&amp;draft_pos%5B%5D=k&amp;draft_pos%5B%5D=p&amp;c5val=1.0&amp;order_by=pass_att&amp;offset=')
  
  offset_seq &lt;- seq(0, 500, 100)
  qb_stats_all &lt;- data.frame()
  
  for(url_end in offset_seq){
    
    print(paste0('Scraping from QB #', url_end, '!'))
    url &lt;- paste0(url_start, url_end)
    data &lt;- htmltab(url, which = 1, rm_nodata_cols = F)
    qb_stats_all &lt;- rbind(qb_stats_all, data)
    
  }
  
  rm(url_start, url_end, offset_seq, url, data)
  
  print('Starting to clean career data')
  # Clean NFL quarterback career data
  colnames(qb_stats_all) &lt;- c('num', 'player', 'start_year', 'end_year', 'draft', 'team', 'league', 'g', 'gs', 'cmp', 'att', 'cmp_pct', 'yds', 'td', 'int', 'td_pct', 'int_pct', 'passing_rate', 'sacked', 'sack_yds', 'yards_per_attempt', 'adj_yards_per_attempt', 'adj_net_yards_per_attempt', 'yds_gained_per_game', 'w', 'l', 't')
  print('no error 1')
  qb_stats_all &lt;- subset(qb_stats_all, select = -c(num)) %&gt;% filter(player != 'Player')
  </code></pre>