我的原始dataframe看起来像这样：
macd_histogram direct event
1.675475e-07 up crossing up
2.299171e-07 up 0
2.246809e-07 up 0
1.760860e-07 up 0
1.899371e-07 up 0
1.543226e-07 up 0
1.394901e-07 up 0
-3.461691e-08 down crossing down
1.212740e-06 up 0
6.448285e-07 up 0
2.227792e-07 up 0
-8.738289e-08 down crossing up
-3.109205e-07 down 0
列事件充满了crossing up和crossing down！我需要的是在crossing up和crossing down之间从macd_histogram列（在相同索引之间）提取最高值，并从最低点提取它，并将其添加到crossing up旁边的新列中！
我尝试使用for循环进行操作，但是我在如何选择每个 crossing up和 crossing down之间的范围有点丢失...有什么帮助吗？谢谢！
我所期望的事实（遵循上述数据框）：
macd_histogram direct event magnitude
1.675475e-07 up crossing up (0.851908-07)
2.299171e-07 up 0
2.246809e-07 up 0
1.760860e-07 up 0
1.899371e-07 up 0
1.543226e-07 up 0
1.394901e-07 up 0
-3.461691e-08 down crossing down (2.651908-06)
1.212740e-06 up 0
6.448285e-07 up 0
2.227792e-07 up 0
-8.738289e-08 down crossing up etc..
-3.109205e-07 down 0
这是我到目前为止尝试的：
index_up = df[df.event == 'crossing up'].index.values
index_down = df[df.event == 'crossing down'].index.values
df['magnitude'] = 0
array = np.array([])
for i in index_up:
for idx in index_down:
values = df.loc[i:idx, 'macd_histogram'].tolist()
max = np.max(values)
min = np.min(values)
magnitutde = max-min
print(magnitude)
df.at[i,'magnitude'] = magnitude
但是我有以下错误消息： ValueError: zero-size array to reduction operation maximum which has no identity
我想我理解您的要求，但是我的结果数字与您的示例不符，所以也许我不完全理解。希望这个很多答案对您有所帮助。
首先创建一个列放置结果。
df['result'] = np.nan
创建一个只有行索引的变量，然后向上/向下。
event_range = df[df['event'] != '0'].index
制作一个循环以循环循环穿过索引阵列。为每个部分创建一个开始和结束索引编号，获取每个开始/结束索引号的最大值和最小范围，然后将其减去并放在右列中。
for x in range(len(event_range)-1):
start = event_range[x]
end = event_range[x+1] +1 # I'm not sure if this is the range you want
max = df.iloc[start:end, 0].max()
min = df.iloc[start:end, 0].min()
diff = max - min
df.iloc[start, 3] = diff
df
macd_histogram direct event result
0 1.675480e-07 up crossing up 2.645339e-07
1 2.299170e-07 up 0 NaN
2 2.246810e-07 up 0 NaN
3 1.760860e-07 up 0 NaN
4 1.899370e-07 up 0 NaN
5 1.543230e-07 up 0 NaN
6 1.394900e-07 up 0 NaN
7 -3.461690e-08 down crossing down 1.300123e-06
8 1.212740e-06 up 0 NaN
9 6.448290e-07 up 0 NaN
10 2.227790e-07 up 0 NaN
11 -8.738290e-08 down crossing up NaN
12 -3.109210e-07 down 0 NaN