title: Does "let _ = ..." (let underscore equal) have any use in Swift?
body: <p>Does using <code>let _ = ...</code> have any purpose at all?</p>
  
  <p>I've seen question and answers for <a href="https://stackoverflow.com/questions/24437388/whats-the-underscore-representative-of-in-swift-references">What&#39;s the _ underscore representative of in Swift References?</a> and I know that the underscore <a href="https://stackoverflow.com/a/24437488/3681880">can be used to represent a variable that isn't needed</a>. </p>
  
  <p>This would make sense if I only needed one value of a tuple as in the example from the above link:</p>
  
  <pre><code>let (result, _) = someFunctionThatReturnsATuple()
  </code></pre>
  
  <p>However, I recently came across <a href="https://github.com/hoffmanjon/SQLiteDataAccessLayer2/blob/master/TestSqliteSwiftV2/DataHelper.swift" rel="noreferrer">this code</a>:</p>
  
  <pre><code>do {
      let _ = try DB.run( table.create(ifNotExists: true) {t in
          t.column(teamId, primaryKey: true)
          t.column(city)
          t.column(nickName)
          t.column(abbreviation)
          })
  
  } catch _ {
      // Error throw if table already exists
  }
  </code></pre>
  
  <p>I don't get any compiler warnings or errors if I just remove the <code>let _ =</code>. It seems to me like this is simpler and more readable.</p>
  
  <pre><code>try DB.run( table.create(ifNotExists: true) {t in
      t.column(teamId, primaryKey: true)
      t.column(city)
      t.column(nickName)
      t.column(abbreviation)
      })
  </code></pre>
  
  <p>The author of the code has written <a href="http://masteringswift.blogspot.com/2015/09/create-data-access-layer-with.html" rel="noreferrer">a book and a blog about Swift</a>. I know that authors aren't infallible, but it made me wonder if there is something I am missing.</p>