title: read.table() and read.csv both Error in Rmd
body: <p>I want to read a txt in Rmd</p>
  
  <pre><code>---
  title: "Untitled"
  output: html_document
  ---
  ```{r}
  country &lt;- read.table("country.txt")
  country
  ```
  </code></pre>
  
  <p>It show error:</p>
  
  <pre><code>processing file: Preview-2878539db5c7.Rmd
  
  Quitting from lines 6-8 (Preview-2878539db5c7.Rmd) 
  Error in file(file, "rt") : cannot open the connection
  Calls: &lt;Anonymous&gt; ... withCallingHandlers -&gt; withVisible -&gt; eval -&gt; eval -&gt; read.table -  &gt; file
  Execution halted
  </code></pre>
  
  <p>But I can run code in R console successfully</p>
  
  <pre><code>&gt; country &lt;- read.table("country.txt")
  
  &gt; country
       production1 education1     fir1 inflation1 lq1 nonstatein1 patent1     tax1   trade1
  2001    52920.47   132649.4 2.339263   0.700000  NA    19562.16  109313 23783.07 23783.07
  2002    65876.57   144090.3 2.500826  -0.800000  NA    24727.30  131972 27479.61 27479.61
  2003    89227.20   156280.4 2.691411   1.168900  NA    34044.45  164611 31537.50 31537.50
  2004    92656.06   167683.7 2.615238   3.878600  NA    45613.10  177364 36179.87 36179.87
  2005   167115.37   171379.7 2.617289   1.810000  NA    77525.52  231570 42008.37 42008.37
  2006   218827.79   181084.6 2.578939   1.467800  NA    77441.52  282315 54866.43 54866.43
  2007   286691.88   192677.9 2.439093   4.772700  NA    99032.26  333059 66453.31 66453.31
  2008   364955.86   202542.8 2.440807   5.864570  NA   124621.23  418524 74104.80 74104.80
  2009   398476.09   213539.2 3.783803  -0.693900  NA   153670.18  537957 65501.69 65501.69
  2010   511364.93   254805.1 3.806066   3.322200  NA   194286.94  700304 81966.57 81966.57
  2011   624657.55   279690.7 2.862413   5.393433  NA   229513.81  997132 91118.75 91118.75
  </code></pre>
  
  <p>The file is existing in wd</p>
  
  <pre><code>&gt; file.exists("country.txt")
  [1] TRUE
  </code></pre>
  
  <p>I also try to use read.csv()
  but it show similar error:</p>
  
  <pre><code>processing file: Preview-28786aad2e0.Rmd
  
  Quitting from lines 6-8 (Preview-28786aad2e0.Rmd) 
  Error in file(file, "rt") : cannot open the connection
  Calls: &lt;Anonymous&gt; ... withVisible -&gt; eval -&gt; eval -&gt; read.csv -&gt; read.table -&gt; file
  Execution halted
  </code></pre>