How do I check a previous row's value, (OHLC Stock Data)?

Question

I'm trying to do data-mine a stock data frame where the signal generated is in this format:

Signal = (stratdf['High'].shift() > (stratdf['Open'].shift()))

How do I code to check the previous row's value and compare it to the corresponding rows value (example: 1 bar ago > 10 bars ago) with the Signal being executed the next day (or row) after the logic is true?

Answer 1

>>> import pandas as pd
>>> df = pd.DataFrame([[4, 5, 9, 7, 10], [5, 4, 11, 8, 9]]).T
>>> df.columns = ['High', 'Open']
>>> df
   High  Open
0     4     5
1     5     4
2     9    11
3     7     8
4    10     9
>>> df['pre_high'] = df['High'].shift(1)
>>> df
   High  Open  pre_high
0     4     5       NaN
1     5     4       4.0
2     9    11       5.0
3     7     8       9.0
4    10     9       7.0

Now if you want to check where the pre_high is greater than the current open, then you can do the following:

>>> df['Signal'] = df['High'].shift(1) > df['Open']
>>> df
   High  Open  pre_high  Signal
0     4     5       NaN   False
1     5     4       4.0   False
2     9    11       5.0   False
3     7     8       9.0    True
4    10     9       7.0   False