<p>下面的代码是用计数器一打印出所有的字符[d,e],但我只需要第一个字符就可以打印出来,我该怎么做?在</p>
<pre><code>def firstNonRepeat(s):
counter = {}
for char in s:
if char in counter:
counter[char] += 1
else:
counter[char] = 1
for char in s:
if counter[char] == 1:
print char
return None
firstNonRepeat('aabccbdcbe')
</code></pre>