擅长:python、mysql、java
<p>一种解决方案是设置默认值0,然后对切片数据帧使用appy:</p>
<pre class="lang-py prettyprint-override"><code>df['Amount C'] = 0 # set default value 0
mask_type = df['type'] == 'c' # build index mask
df.loc[mask_type, 'Amount C'] = df.loc[mask_type].apply(lambda x: node_counter(x['id_x'], df['parentId']), axis=1)
</code></pre>