How to get length of byte slice content?

<p>How can I get length (int) of byte slice content? I need to read to the last byte, for position != length { }</p> <p>The slice content length is 202. However, when I use len(data) it returns 4084 which is probably the buffer size, not the size of the buffer content.</p> <hr/>**评论：**<br/><br/>chickenphobia: <pre><p>Can you rephrase this? Maybe with a stub example showing expected behavior?</p> <p>As currently worded, sounds like you should use the len() built-in</p> <pre><code>lastByte := myByteSlice[len(myByteSlice) - 1] </code></pre></pre>win32re: <pre><p>Well, in this case, the slice content length is 202. However, when I use len(data) it returns 4084 which is probably the buffer size, not the size of the buffer content.</p></pre>davecheney: <pre><p>Are you reslicing the []byte after the call to Read ?</p></pre>win32re: <pre><p>That was the problem, after reslicing it everything works fine. Thanks!</p></pre>mperham: <pre><p>I suspect you are talking about the difference between len() and cap(). <a href="http://golang.org/doc/effective_go.html#slices" rel="nofollow">http://golang.org/doc/effective_go.html#slices</a></p></pre>jerf: <pre><p>The local answer is that <a href="http://play.golang.org/p/q9zgarI6dB" rel="nofollow">len gives the length of a byte slice</a>.</p> <p>The global answer is that it sounds like you want <a href="http://golang.org/pkg/io/#ReadFull" rel="nofollow"><code>io.ReadFull</code></a>. <code>io.ReadFull</code> nicely collapses the space of possible behaviors to &#34;you got that many bytes&#34;, &#34;the stream ended before you got that many bytes&#34;, and &#34;the function never returned because it&#39;s still waiting for bytes&#34;. If this is a network, combine it with timeouts on the socket and you can also essentially remove that third possibility. This all combines to make networking code reasonably pleasant to write.</p></pre>win32re: <pre><p>Fixed. I didn&#39;t use the length from conn.Read and my buffer size was set to 4096. Therefore, len(buf) was returning a big buffer size which was correct but due to me not reslicing the buffer it was wrong.</p></pre>