the built-in function <a href="#Length_and_capacity"><code>len</code></a>.
The length is a compile-time constant if the string is a constant.
A string's bytes can be accessed by integer <a href="#Index_expressions">indices</a>
0 through <code>len(s)-1</code>.
It is illegal to take the address of such an element; if
<code>s[i]</code> is the <code>i</code>'th byte of a
string, <code>&amp;s[i]</code> is invalid.
</p>