title: How to selectively execute functions and accumulate result
body: <p>I would like to create a result-vector of a sub-group of functions.</p>
  
  <p>This is a simplified example of what I mean:</p>
  
  <pre><code># create example functions
  set.seed(999)
  
  create_fun &lt;- function(start, len) {
    res &lt;- function() {
      seq(from = start, length.out = len)
    }
    res
  }
  
  for (i in 1:4) {
    eval(parse(text = paste0("f", i, "&lt;-create_fun(", sample(1:10, 1), ",",     sample(2:5, 1), ")")))
    # btw is it possible to use something like assign instead of eval-parse?
  }
  
  # static version of what I want
  c(f1(), f3(), f4())
  # 4 5 6 7 8 9 7 8
  
  # dynamic version of what I want
  x &lt;- c(f1 = TRUE, f2 = FALSE, f3 = TRUE, f4 = TRUE) # I'd like to start with a vector of function-names to use
  # .. but now what?
  </code></pre>
  
  <p>How to do this properly?</p>