title: R- check unique values by all members in group
body: <p>I have a data like this:</p>
  
  <pre class="lang-r prettyprint-override"><code>taxes_sol &lt;- structure(list(type_tax = c(
    "good1", "good2", "good1", "good2",
    "good1", "good2", "good1", "good2",
    "good1", "good2", "good1", "good2"
  ), sol = c("x1", "x1", "x2", "x2", "x3", "x3", "x4", "x4", "x5", "x5", "x6", "x6"
  ), tax = c("0.11", "0.16", "0.09", "0.15", "0.11", "0.17",
    "0.09", "0.15", "0.21", "0.33", "0.11", "0.16"
  )), row.names = c(NA, -12L), class = c("tbl_df", "tbl", "data.frame"))
  </code></pre>
  
  <p>And I want to keep the solutions where the taxes are different. In this case it would be to keep only the solutions: "x1", "x2", "x3" and "x5".</p>
  
  <p>So I tried to do it with <code>distintc()</code> and grouping by type_tax and tax:</p>
  
  <pre class="lang-r prettyprint-override"><code>taxes_sol %&gt;% 
    distinct(type_tax, tax, .keep_all = T)
  </code></pre>
  
  <p>But that doesn’t return the good1 for "x3" solution.</p>