title: Losing data while saving csv character file
body: <p>i have a very stupid problem that made me loose a few hours, hence I though about posting it here. </p>
  
  <p>my data looks something like this</p>
  
  <pre><code>df&lt;- data.frame("Reporter" = c("USA", "USA", "USA", "USA", 
  "Africa","Africa", "Africa","Africa"), 
  "Partner" = c("Africa", "Africa", "EU", "EU", 
  "USA", "USA", "EU", "EU"),
  "Year" = c(1970, 1980, 1970, 1980, 1970, 1980, 
  1970, 1980), 
  "Flow" = c("001", "00", "1", "112", "0", "2", "23", "TOT"),
  "Val" = runif(8, min=0, max=100), stringsAsFactors 
  = FALSE)     
  </code></pre>
  
  <p>Flow is a character variable that include character and numbers. These are identifiers for the variable "Val"</p>
  
  <pre><code>class(df$Flow)
  </code></pre>
  
  <p>I would like to remove the rows that have letters in "Flow" while keeping the rest.</p>
  
  <pre><code>df &lt;- df %&gt;% filter(Flow != "TOT")
  </code></pre>
  
  <p>this approach works as I expect. 
  The problem appears later once I remove the letters from flow, and save  my data csv.</p>
  
  <pre><code> write.csv(df, "df.csv")
  </code></pre>
  
  <p>Once I re-upload my data, this has been radically transformed. All the 0s in front of number have been lost as the data has been stored as numeric </p>
  
  <pre><code> df2&lt;- import("df.csv")
  </code></pre>
  
  <p>I have also tried <code>write.csv2(df, "df.csv")</code> but the result does not change. 
  If I save in dta instead, the data work once re-uploaded, but I would like to save in csv</p>
  
  <p>Does anyone know what I am doing wrong?</p>