数据帧的百分比变化

Question

I a此数据帧代码：

analytics = q1.groupby(['Year','YearMonth','glnumber','nom'])[['amount']].sum().reset_index()
#add previous sales to the next row
analytics['prev_$'] = analytics['amount'].shift(1)
#drop the null values and calculate the difference
analytics = analytics.dropna()
analytics['diff'] = (analytics['amount'] - analytics['prev_$'])
analytics = analytics.drop(['prev_$'],
  axis='columns')

我试图通过将分析['prev\$']除以分析['amount']来计算变化的百分比

这是我的代码：

analytics['Perc_diff'] = analytics.apply(0 if analytics['amount'] == 0 else divide(analytics['diff'], analytics['amount']))

但我有一个错误： ValueError：序列的真值不明确。使用a.empty、a.bool（）、a.item（）、a.any（）或a.all（）

Answer 1

您可以使用np.where进行此操作：

import numpy as np
analytics['Perc_diff'] = np.where(analytics['amount']==0,0,analytics['diff']/analytics['amount'])