擅长:python、mysql、java
<p>您期望的输出与输入完全相同,只是id4和id6在一起,而nan位于不同的位置。不可能有那样的预期产出。你知道吗</p>
<p>以下是组员的理想工作方式:</p>
<pre><code>print("Original: ")
print(df)
df = df.fillna(-1) # if not replaced with another character , the grouping won't show NaNs.
df2 = df.groupby('_Parent')
print("\nAfter grouping: ")
for key, item in df2:
print (df2.get_group(key))
</code></pre>
<p>输出:</p>
<pre><code>Original:
_Id _Parent
0 1 NaN
1 2 NaN
2 3 1.0
3 4 2.0
4 5 NaN
5 6 2.0
After grouping:
_Id _Parent
0 1 0.0
1 2 0.0
4 5 0.0
_Id _Parent
2 3 1.0
_Id _Parent
3 4 2.0
5 6 2.0
</code></pre>