<p>以下if语句是否满足此条件:</p>
<blockquote>
<p>If the set increases in size (indicating this word has not been processed before), add the word to the dict as a key with the value being the new length of the set</p>
</blockquote>
<p>还是我找错树了?你知道吗</p>
<pre><code>s = set()
d = dict()
text = input("Your text here: ")
for word in text.strip().split():
if word not in s:
s.add(word)
d[word] = len(s)
print(d)
</code></pre>
<p>也许更简单的方法</p>
<pre><code>d = dict()
for word in raw_input('enter:').strip().split():
if word not in d:
d[word]=len(word)
print d.keys()
</code></pre>