title: How to fmt.Printf an integer with thousands comma
body: <p>Does Go's <code>fmt.Printf</code> support outputting a number with the thousands comma?</p>
  
  <p><code>fmt.Printf("%d", 1000)</code> outputs <code>1000</code>, what format can I specify to output <code>1,000</code> instead?</p>
  
  <p>The <a href="http://golang.org/pkg/fmt/" rel="noreferrer">docs</a> don't seem to mention commas, and I couldn't immediately see anything in the <a href="https://code.google.com/p/go/source/browse/src/pkg/fmt/" rel="noreferrer">source</a>.</p>