title: dplyr r : selecting columns whose names are in an external vector
body: <h1>Purpose</h1>
  <p>Can I select columns using <code>dplyr</code> conditional that the column name is in an external vector. I have found some posts that explain how to subset the data frame using a vector of name, but I could not find one when some of the names in the vector do not exist in the data frame.</p>
  <h1>Example dataset</h1>
  <pre><code>  library(tidyverse)
    library(tibble)
    library(data.table)
    
    col_names &lt;- c('a', 'b', 'e')
    
    rename &lt;- dplyr::rename
    select &lt;- dplyr::select
    
    set.seed(10002)
    a &lt;- sample(1:20, 1000, replace=T)
    
    set.seed(10003)
    b &lt;- sample(letters, 1000, replace=T)
    
    set.seed(10004)
    c &lt;- sample(letters, 1000, replace=T)
    
    
    data &lt;-   
      data.frame(a, b, c) 
  # I would like to choose a, b that are in col_names vector. 
  </code></pre>