Find the first signal in a condition

Question

I have a data frame (df) with different "price"s and I want to compare these prices and make a decision.

df['Decision'] = np.where((df['price1'] > df['price2']) ,'sell',np.where((df['price1'] < df['price2']),'buy',np.nan))

My output is:

But I want to have just the "first signal" of "buy" or "sell" and delete replication until the next signal, as:

It solves my question: https://stackoverflow.com/questions/64269453/pandas-replace-duplicates-with-nan-and-keep-row — SA12, May 31 '21 at 07:13

score 2 · Answer 1 · edited May 30 '21 at 10:26

2

You can try with idxmax:

df.loc[(df['price1'] > df['price2']).idxmax(), 'Decision'] = 'sell'
df.loc[(df['price1'] < df['price2']).idxmax(), 'Decision'] = 'buy'

edited May 30 '21 at 10:26

Tomerikoo

answered May 30 '21 at 08:54

Nk03

It gets the first table, not the second. I don't want to have the same signals until the decision changing. – SA12 May 31 '21 at 05:38

1 Answers1