遍历行以查看哪个值最先出现

Question

在使用Pandas时，我可以使用.shift（）检查前面和后面的行，以查看是否满足某些条件。你知道吗

如果我需要查看是否满足一个条件，即在我比较的行之后可能是100行或更多行，该怎么办？我知道在数据帧中循环不是最有效的，但是有人能帮我举个例子吗。你知道吗

当df['reversion']列有一个信号时（如下面14:00显示6.0的示例所示），我想知道在14:00行之后首先看到的是以下哪一个：

• df.price，值为df.reversal+1（我们可以看到这是在20:00命中的，因为6+1=7）
• df.price的值为df.reversal-df.reversal（在本例中，由于价格未达到6-6=0，因此未达到该值）

这是我想要看到的蓝色单元格的输出。新列应该显示达到目标的时间（根据本例）或未达到目标的时间（如果本例中价格达到0）。你知道吗

请参见下面的df.to_dict()来复制：

{'move_start': {datetime.time(9, 0): nan,
  datetime.time(10, 0): nan,
  datetime.time(11, 0): nan,
  datetime.time(12, 0): nan,
  datetime.time(13, 0): nan,
  datetime.time(14, 0): datetime.time(9, 0),
  datetime.time(15, 0): nan,
  datetime.time(16, 0): nan,
  datetime.time(17, 0): nan,
  datetime.time(18, 0): nan,
  datetime.time(19, 0): nan,
  datetime.time(20, 0): nan},
 'price': {datetime.time(9, 0): 1,
  datetime.time(10, 0): 2,
  datetime.time(11, 0): 3,
  datetime.time(12, 0): 4,
  datetime.time(13, 0): 5,
  datetime.time(14, 0): 6,
  datetime.time(15, 0): 5,
  datetime.time(16, 0): 4,
  datetime.time(17, 0): 3,
  datetime.time(18, 0): 2,
  datetime.time(19, 0): 4,
  datetime.time(20, 0): 7},
 'reversal': {datetime.time(9, 0): nan,
  datetime.time(10, 0): nan,
  datetime.time(11, 0): nan,
  datetime.time(12, 0): nan,
  datetime.time(13, 0): nan,
  datetime.time(14, 0): 6.0,
  datetime.time(15, 0): nan,
  datetime.time(16, 0): nan,
  datetime.time(17, 0): nan,
  datetime.time(18, 0): nan,
  datetime.time(19, 0): nan,
  datetime.time(20, 0): nan}}

Answer 1

把它弄得更好更干净，我想。。。你知道吗

import datetime,numpy as np,pandas as pd
nan = np.nan

a = pd.DataFrame({'move_start': {datetime.time(9, 0): nan,   datetime.time(10, 0): nan,   datetime.time(11, 0): nan,   datetime.time(12, 0): nan,   datetime.time(13, 0): nan,   datetime.time(14, 0): datetime.time(9, 0),   datetime.time(15, 0): nan,   datetime.time(16, 0): nan,   datetime.time(17, 0): nan,   datetime.time(18, 0): nan,   datetime.time(19, 0): nan,   datetime.time(20, 0): nan},  'price': {datetime.time(9, 0): 1,   datetime.time(10, 0): 0,   datetime.time(11, 0): 3,   datetime.time(12, 0): 4,   datetime.time(13, 0): 7,   datetime.time(14, 0): 6,   datetime.time(15, 0): 5,   datetime.time(16, 0): 4,   datetime.time(17, 0): 0,   datetime.time(18, 0): 2,   datetime.time(19, 0): 4,   datetime.time(20, 0): 7},  'reversal': {datetime.time(9, 0): nan,   datetime.time(10, 0): nan,   datetime.time(11, 0): nan,   datetime.time(12, 0): nan,   datetime.time(13, 0): nan,
  datetime.time(14, 0): 6.0,   datetime.time(15, 0): nan,   datetime.time(16, 0): nan,   datetime.time(17, 0): nan,   datetime.time(18, 0): nan,   datetime.time(19, 0): nan,   datetime.time(20, 0): nan}})


a['target_hit']=nan;
a['target_miss']=nan;
a['reversal1']=a['reversal']+1;
a['reversal2']=a['reversal']-a['reversal'];
a.sort_index(1,inplace=True);

hit = a.ix[:,:-2].dropna()

takeBoth = False
targetIsHit,targetIsMiss = False,False

if takeBoth:

    targetHit = a[(hit['reversal1'].values==a['price'].values) & (hit['reversal1'].index.values<a['price'].index.values)];
    targetMiss = a[(hit['reversal2'].values==a['price'].values) & (hit['reversal2'].index.values<a['price'].index.values)];

    targetIsHit,targetIsMiss = not targetHit.empty, not targetMiss.empty

else:

    targetHit = a[(hit['reversal1'].values==a['price'].values) & (hit['reversal1'].index.values<a['price'].index.values)];
    targetIsHit = not targetHit.empty
    if not targetIsHit:
         targetMiss = a[(hit['reversal2'].values==a['price'].values) & (hit['reversal2'].index.values<a['price'].index.values)]; 
         targetIsMiss = not targetMiss.empty

if targetIsHit:a.loc[hit.index.values,"target_hit"] = targetHit.index.values;
if targetIsMiss:a.loc[hit.index.values,"target_miss"] = targetMiss.index.values;

print '#'*50
print a
'''
##################################################
         move_start  price  reversal  reversal1  reversal2 target_hit  \
09:00:00        NaN      1       NaN        NaN        NaN        NaN   
10:00:00        NaN      0       NaN        NaN        NaN        NaN   
11:00:00        NaN      3       NaN        NaN        NaN        NaN   
12:00:00        NaN      4       NaN        NaN        NaN        NaN   
13:00:00        NaN      7       NaN        NaN        NaN        NaN   
14:00:00   09:00:00      6       6.0        7.0        0.0   20:00:00   
15:00:00        NaN      5       NaN        NaN        NaN        NaN   
16:00:00        NaN      4       NaN        NaN        NaN        NaN   
17:00:00        NaN      0       NaN        NaN        NaN        NaN   
18:00:00        NaN      2       NaN        NaN        NaN        NaN   
19:00:00        NaN      4       NaN        NaN        NaN        NaN   
20:00:00        NaN      7       NaN        NaN        NaN        NaN   

          target_miss  
09:00:00          NaN  
10:00:00          NaN  
11:00:00          NaN  
12:00:00          NaN  
13:00:00          NaN  
14:00:00          NaN  
15:00:00          NaN  
16:00:00          NaN  
17:00:00          NaN  
18:00:00          NaN  
19:00:00          NaN  
20:00:00          NaN
'''

PS：作为典型的pythonist，我很懒，喜欢处理包含最典型问题的普通输入/输出，所以你让beggining变成了一个讨厌的df，而不是只写XD。。。关于阅读文本。。。人们倾向于写，写，写。通常这是一个简单的问题，但hella wroten，所以我不理解yota xD。然后就好像“他想要这里吗？！”。你知道吗