擅长:python、mysql、java
<p><code>if flag == x</code>看起来很奇怪。你希望<code>x</code>的值是多少?你知道吗</p>
<p>我建议将<code>flag</code>初始化为<code>None</code>,然后在循环的末尾检查它是否不是<code>None</code>。你知道吗</p>
<pre><code>flag = None # assign a "sentinel" value here
str = "gram chara oi ranga matir poth"
find = 'p'
for x in range(len(str)):
if str[x] == find:
flag = x
# Leaving out the break is also fine. It means you'll print the
# index of the last occurrence of the character rather than the first.
break
if flag is not None:
print "found in index no", flag
else:
print "not found in there"
</code></pre>