CODEWITHSUNDEEP
pythonpandasdataframe
Dharmesh
Dharmesh

Reputation: 53

dataframe value comparison in python

Team, I have a huge pandas data frame of historical stock OHLC data. I want to compare a particular column value , for e.g. I want to compare today's open with yesterdays open or today's low with yesterdays low ( I have almost 5000 rows to compare )

I tried something like followed, but it gives me just one constant value..

#calculate Low Travel point
df['1back'] = df['low'].iloc[-1]

any suggestion plese??

Upvotes: 2

Views: 109

Answers (2)

Dharmesh
Dharmesh

Reputation: 53

calculate EMA/SMA togllers

filter_EMA_TOGGLER_Steady = df['EMA_CROSS'] ==  df['EMA_CROSS'].shift(-1)
filter_EMA_TOGGLER_BUY = (df['EMA_CROSS'] == 'SELL') &  (df['EMA_CROSS'].shift(-1) == 'BUY')
filter_EMA_TOGGLER_SELL = (df['EMA_CROSS'] == 'BUY') &  (df['EMA_CROSS'].shift(-1) == 'SELL')
#SMA 
filter_SMA_TOGGLER_Steady = df['SMA_CROSS'] ==  df['SMA_CROSS'].shift(-1)
filter_SMA_TOGGLER_BUY = (df['SMA_CROSS'] == 'SELL') &  (df['SMA_CROSS'].shift(-1) == 'BUY')
filter_SMA_TOGGLER_SELL = (df['SMA_CROSS'] == 'BUY') &  (df['SMA_CROSS'].shift(-1) == 'SELL')

Upvotes: 0

Rikki
Rikki

Reputation: 3518

This code:

import pandas as pd


df = pd.DataFrame([
    [10, 102],
    [12, 98],
    [13, 99],
    [15, 94]
],
    columns=['p1', 'p2']
)

print(df.head(10))

df['p1_diff'] = df['p1'].diff(1)
df['p2_diff'] = df['p2'].diff(1)

print(df.head(10))

Should provide the following output:

   p1   p2
0  10  102
1  12   98
2  13   99
3  15   94
   p1   p2  p1_diff  p2_diff
0  10  102      NaN      NaN
1  12   98      2.0     -4.0
2  13   99      1.0      1.0
3  15   94      2.0     -5.0

Process finished with exit code 0

What you look for is diff. Reference here.

Upvotes: 2

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