title: sapply - retain column names
body: <p>I am trying to summarise the mean, sd etc for a number of different columns (variables) in my dataset. I have coded my own summarise function to return exactly what I need and am using sapply to apply this function to all the variables at once. It works fine, however the dataframe that is returned has no column names and I cannot seem to even rename them using a column number reference - aka they seem impossible to use in any way.</p>
  
  <p>My code is below- as I am just finding summary statistics, I would like to just keen the same column (variable) names, with 4 rows (mean, sd, min, max). Is there any way at all to do this (even a slow way where I manually change the names of the columns)</p>
  
  <pre><code> #GENERATING DESCRIPTIVE STATISTICS
  sfsum= function(x){
    mean=mean(x)
    sd=sd(x)
    min=min(x)
    max=max(x)
  
    return(c(mean,sd,min,max))
  }
  
  #
  c= list(sfbalanced$age_child, sfbalanced$earnings_child, 
  sfbalanced$logchildinc ,sfbalanced$p_inc84, sfbalanced$login84, 
  sfbalanced$p_inc85, sfbalanced$login85, sfbalanced$p_inc86, 
  sfbalanced$login86, sfbalanced$p_inc87, sfbalanced$login87, 
  sfbalanced$p_inc88, sfbalanced$login88)
  
  summ=sapply(c,sfsum)
  
  names(summ)
   NULL
  </code></pre>