擅长:python、mysql、java
<p>使用<strong><a href="https://docs.python.org/3/library/ast.html" rel="nofollow noreferrer">ast module</a></strong>将字符串列表转换为list对象并获得len</p>
<pre><code>import ast
a = ast.literal_eval("['3']") #print(len(ast.literal_eval(query[0]['myvalue'])))
b = ast.literal_eval("['1', '4']")
print len(a) # returns 1
print len(b) # returns 2
</code></pre>