title: Filter by multiple patterns with filter() and str_detect()
body: <p>I would like to filter a dataframe using filter() and str_detect() matching for multiple patterns without multiple str_detect() function calls. In the example below I would like to filter the dataframe <code>df</code> to show only rows containing the letters <code>a</code> <code>f</code> and <code>o</code>.</p>
  
  <pre><code>df &lt;- data.frame(numbers = 1:52, letters = letters)
  df %&gt;%
      filter(
          str_detect(.$letters, "a")|
          str_detect(.$letters, "f")| 
          str_detect(.$letters, "o")
      )
  #  numbers letters
  #1       1       a
  #2       6       f
  #3      15       o
  #4      27       a
  #5      32       f
  #6      41       o
  </code></pre>
  
  <p>I have attempted the following </p>
  
  <pre><code>df %&gt;%
      filter(
          str_detect(.$letters, c("a", "f", "o"))
       )
  #  numbers letters
  #1       1       a
  #2      15       o
  #3      32       f
  </code></pre>
  
  <p>and receive the following error</p>
  
  <blockquote>
    <p>Warning message: In stri_detect_regex(string, pattern, opts_regex =
    opts(pattern)) :   longer object length is not a multiple of shorter
    object length</p>
  </blockquote>