Why doesn't math package contains such obvious function as round?

<p>Any explanation? Thanks.</p> <hr/>**评论：**<br/><br/>emersion_fr: <pre><p>Go 1.10 will have a math.Round function.</p></pre>cdoxsey: <pre><p>There&#39;s a long history on this issue: <a href="https://github.com/golang/go/issues/20100">https://github.com/golang/go/issues/20100</a></p> <p>I think the discussion got mired in the fact that there are different ways to round numbers. int(x+0.5) is a simple workaround.</p></pre>emersion_fr: <pre><p>Note that this workaround doesn&#39;t work with negative numbers. See <a href="/u/Zy14rk">/u/Zy14rk</a>&#39;s reply for a correct solution.</p></pre>kerakk19: <pre><p>Thanks for that workaround, didn&#39;t even thought about it.</p></pre>anonfunction: <pre><p>Shameless plug: I have a stats package with round and lots of other common functions. </p> <p>It&#39;s open source on github: https//github.com/montanaflynn/stats</p></pre>Zy14rk: <pre><p>Because reasons! So there!</p> <p>Honestly, I don&#39;t know. Seems like such a natural thing to include. Maybe in 2.0 :)</p> <p>Meanwhile:</p> <pre><code>func round(num float64) int { return int(num + math.Copysign(0.5, num)) } </code></pre></pre>sh41: <pre><p>This should also work:</p> <pre><code>// round rounds f to a nearby int. func round(f float64) int { if f &gt;= 0 { return int(f + 0.5) } else { return int(f - 0.5) } } </code></pre></pre>belak51: <pre><p>These implementations don&#39;t quite work, as described in the issue. This will round 0.5 to 1 (and -0.5 to -1) which probably isn&#39;t what&#39;s intended. </p> <p>This is probably why the proposal was accepted. There are lots of edge cases and it&#39;s easy to have mostly working versions which are still subtly broken.</p></pre>sh41: <pre><p>Well, it does what the comment says, round to a nearby int. It didn&#39;t promise rounding towards zero. But I agree, a more well behaved round func would be more complex.</p></pre>sh41: <pre><p>Round what type to what type?</p></pre>kerakk19: <pre><p>Well, most obvious is the float64 to int, but can be also float64 to float64, with declared round point(default .5) and amount of decimal places </p></pre>Fireynis: <pre><p>Rounding is not an easy task to generalize. There are so many types of rounding. Really there should be like 10 round functions not just one. Check out bankers rounding.</p></pre>pobody: <pre><p>That&#39;s funny, every other language in the past 30 years has managed it. Seems like it would be a solved problem by now.</p></pre>Fireynis: <pre><p>I&#39;m not saying it&#39;s not solvable, nor is it poorly defined. But it&#39;s as simple as &gt; 5 round up. </p></pre>slowratatoskr: <pre><p>it&#39;s like asking why go doesn&#39;t have generics</p></pre>