<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>
<p>尝试以下操作:从字符串中删除一个实例(字符),然后查看其余部分中是否存在该字符:</p>
<pre><code>def firstNonRepeat(s):
for i, char in enumerate(s):
# print i, char, s[i+1:]
if char not in s[:i]+s[i+1:]:
print char
return
firstNonRepeat('aabccbdcbe')
</code></pre>