Detecting almost duplicate rows

Question

Let\'s say I have a table that has dates and a value for each date (plus other columns). I can find the rows that have the same value on the same day by using

Answer 1

use numpy and triangle indexing to map all combinations

day = df.DAY.values
val = df.VALUE.values

i, j = np.triu_indices(len(df), k=1)
c1 = np.abs(day[i] - day[j]) < 2
c2 = np.abs(val[i] - val[j]) < 10

c = c1 & c2
df.iloc[np.unique(np.append(i[c], j[c]))]

    DAY  MTH   YYY  VALUE    NAME
1    22    9  2016   43.0    John
6    24    8  2016   10.0    Mike
7    24    9  2016   10.0    Mike
8    24   10  2016   10.0    Mike
9    24   11  2016   10.0    Mike
10   13    9  2016  170.0  Kathie
11   13   10  2016  170.0  Kathie
13    8    9  2016   16.0    Gina
14    9   10  2016   16.0    Gina
15    8   11  2016   16.0    Gina
17   21   11  2016   45.0    Ross
18   23    9  2016   50.0   Shari
19   23   10  2016   50.0   Shari
20   23   11  2016   50.0   Shari