PROSAGA码农传奇-数据融合-所选行的Pandas数据框的聚合

所选行的Pandas数据框的聚合

作者: 听风～
发布时间: 2024-12-18 10:40:29 (9天前)
转自：

<div class =“post-text”itemprop =“text”>
  <P>
    一种方法是创建一些临时列
  </p>
   <pre>
    <code>
      # First create a new series, which is true whenever the value changes from a zero value to a non-zero value (which will be at the start of each group)
nonzero = (df['Value1'] > 0) & (df['Value1'].shift(1) == 0)
# Take a cumulative sum. This means each group will have it's own number.
df['group'] = df['nonzero'].cumsum()
# Group by the group column
gb = df[df['Value1'] > 0].groupby('group')

</code>
  </pre>
  <P>
    然后，您可以使用聚合函数获取此组的聚合
    <a href="http://pandas.pydata.org/pandas-docs/stable/groupby.html" rel="nofollow noreferrer">
      http://pandas.pydata.org/pandas-docs/stable/groupby.html
    </A>
  </p>
  <P>
    对于您特别希望获得的输出，请看一下这个答案：
    <a href="https://stackoverflow.com/questions/12589481/python-pandas-multiple-aggregations-of-the-same-column">
      Python Pandas：同一列的多个聚合
    </A>
  </p>
   <pre>
    <code>
      df2 = gb.agg({
    'ActivityDateTime': ['first', 'last'],
    'Value1': 'mean',
    'Value2': 'mean'})

</code>
  </pre>
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