擅长:python、mysql、java
<p><code>i</code>是循环中的一个局部变量,它包含<code>s</code>所包含的数字。重新分配变量不会影响它最初保存的数据</p>
<p>这类似于这不会改变<code>a</code>:</p>
<pre><code>a = 1
b = a # This is somewhat what's happening with `for i`
b += 1 # And this is comparable to i += 1
print(a, b) # Will print 1 2, not 2 2
</code></pre>