title: Remove the "X" letter from the column names of a new dataframe
body: <p>I am trying to group by <code>year</code> and sum the <code>weight</code> for each <code>year</code> but when my new data frame is created the column names begin with an annoying "X" like "<code>X2000</code>" instead of <code>2000</code>. Of course I could just delete it or replace it with "<code></code>" after creation but I want it not be created from the very beginning since this method will be applied to dataframes with more columns.  </p>
  
  <pre><code>library(tidyverse)
  
  year&lt;-c("2000","2000","2001","2002","2000","2002")
  weight&lt;-c(0.5,0.7,0.8,0.7,0.6,0.9)
  YG&lt;-data.frame(year,weight)
  
  
  w&lt;-data.frame(YG %&gt;%
                       group_by(year) %&gt;%
                       summarise(n = round(sum(weight)),
                                 g = n()) %&gt;%
                       select(-g) %&gt;%
                       spread(year, n, fill = 0))
  </code></pre>