Create New Column That Compares Across Rows In Pandas Dataframe

I am looking to create a new column in a dataframe based on the values seen in the next 2 rows. Specifically, if any values in the next 2 rows are below 4, then I want the new val

Solution 1:

You can set the new value to one and then use loc together with shift and lt (less than) to set the appropriate values to zero.

df = pd.DataFrame({"A": [5, 6, 7, 8, 2]})
df['new'] = 1

df.loc[(df.A.shift(-1).lt(4)) | (df.A.shift(-2).lt(4)), 'new'] = 0

# The last value does not have any future observations and should be set to zero.
df.new.iat[-1] = 0

>>> df
   A  new
0  5    1
1  6    1
2  7    0
3  8    0
4  2    0

To expand to the next 8 rows instead of 2:

nrows = 8
df.loc[eval(" | ".join("df.A.shift(-{0}).lt(4)".format(n) 
                       for n in range(1, nrows + 1))), 'new'] = 0