Duplicates¶

When merging different data sources, we’re likely to end up with duplicates that can add a lot of bias to and skew our data. Just imagine running a Telco marketing campaign and not removing your duplicates: you’ll end up targeting the same person multiple times!

Let’s use the iris dataset to understand the tools VerticaPy gives you for handling duplicate values.

from verticapy.datasets import load_iris

iris = load_iris()
iris = iris.append(load_iris().sample(3)) # adding some duplicates
iris.head(100)

	123 SepalLengthCm Numeric(7) 100%	...	123 PetalWidthCm Numeric(7) 100%	Abc Species Varchar(30) 100%
1	4.6	...	0.2	Iris-setosa
2	4.7	...	0.2	Iris-setosa
3	4.7	...	0.2	Iris-setosa
4	4.8	...	0.1	Iris-setosa
5	4.8	...	0.2	Iris-setosa
6	4.8	...	0.2	Iris-setosa
7	4.9	...	0.2	Iris-setosa
8	4.9	...	0.1	Iris-setosa
9	4.9	...	0.1	Iris-setosa
10	4.9	...	0.1	Iris-setosa
11	5.0	...	1.0	Iris-versicolor
12	5.0	...	0.2	Iris-setosa
13	5.1	...	0.2	Iris-setosa
14	5.4	...	1.5	Iris-versicolor
15	5.4	...	0.4	Iris-setosa
16	5.4	...	0.4	Iris-setosa
17	5.5	...	1.0	Iris-versicolor
18	5.5	...	1.1	Iris-versicolor
19	5.6	...	1.3	Iris-versicolor
20	5.7	...	1.2	Iris-versicolor
21	5.7	...	0.4	Iris-setosa
22	5.8	...	2.4	Iris-virginica
23	5.9	...	1.8	Iris-versicolor
24	6.1	...	1.4	Iris-versicolor
25	6.1	...	1.8	Iris-virginica
26	6.3	...	1.5	Iris-versicolor
27	6.3	...	1.6	Iris-versicolor
28	6.3	...	2.5	Iris-virginica
29	6.4	...	1.3	Iris-versicolor
30	6.5	...	1.8	Iris-virginica
31	6.5	...	2.2	Iris-virginica
32	6.7	...	1.7	Iris-versicolor
33	6.8	...	1.4	Iris-versicolor
34	6.8	...	2.3	Iris-virginica
35	7.0	...	1.4	Iris-versicolor
36	7.1	...	2.1	Iris-virginica
37	7.7	...	2.2	Iris-virginica
38	4.4	...	0.2	Iris-setosa
39	4.5	...	0.3	Iris-setosa
40	4.8	...	0.2	Iris-setosa
41	5.0	...	1.0	Iris-versicolor
42	5.1	...	0.5	Iris-setosa
43	5.1	...	0.2	Iris-setosa
44	5.2	...	1.4	Iris-versicolor
45	5.2	...	0.2	Iris-setosa
46	5.2	...	0.1	Iris-setosa
47	5.4	...	0.4	Iris-setosa
48	5.5	...	0.2	Iris-setosa
49	5.6	...	1.3	Iris-versicolor
50	5.8	...	1.2	Iris-versicolor
51	5.8	...	1.9	Iris-virginica
52	5.8	...	1.9	Iris-virginica
53	5.9	...	1.5	Iris-versicolor
54	5.9	...	1.8	Iris-virginica
55	6.0	...	1.6	Iris-versicolor
56	6.0	...	1.5	Iris-versicolor
57	6.1	...	1.2	Iris-versicolor
58	6.2	...	1.8	Iris-virginica
59	6.2	...	1.3	Iris-versicolor
60	6.3	...	1.3	Iris-versicolor
61	6.3	...	1.8	Iris-virginica
62	6.4	...	2.3	Iris-virginica
63	6.5	...	1.5	Iris-versicolor
64	6.5	...	2.0	Iris-virginica
65	6.5	...	2.0	Iris-virginica
66	6.6	...	1.3	Iris-versicolor
67	6.6	...	1.4	Iris-versicolor
68	6.7	...	1.4	Iris-versicolor
69	6.7	...	1.5	Iris-versicolor
70	6.9	...	1.5	Iris-versicolor
71	6.9	...	2.1	Iris-virginica
72	6.9	...	2.3	Iris-virginica
73	7.2	...	1.6	Iris-virginica
74	7.2	...	1.8	Iris-virginica
75	7.3	...	1.8	Iris-virginica
76	7.7	...	2.3	Iris-virginica
77	3.3	...	7.8	Iris-setosa
78	3.3	...	7.8	Iris-setosa
79	3.3	...	7.8	Iris-setosa
80	3.3	...	7.8	Iris-setosa
81	3.3	...	7.8	Iris-setosa
82	3.3	...	7.8	Iris-setosa
83	3.3	...	7.8	Iris-setosa
84	3.3	...	7.8	Iris-setosa
85	3.3	...	7.8	Iris-setosa
86	3.3	...	7.8	Iris-setosa
87	3.3	...	7.8	Iris-setosa
88	3.3	...	7.8	Iris-setosa
89	3.3	...	7.8	Iris-setosa
90	3.3	...	7.8	Iris-setosa
91	3.3	...	7.8	Iris-setosa
92	3.3	...	7.8	Iris-setosa
93	3.3	...	7.8	Iris-setosa
94	3.3	...	7.8	Iris-setosa
95	3.3	...	7.8	Iris-setosa
96	3.3	...	7.8	Iris-setosa
97	3.3	...	7.8	Iris-setosa
98	3.3	...	7.8	Iris-setosa
99	3.3	...	7.8	Iris-setosa
100	3.3	...	7.8	Iris-setosa

To find all the duplicates, you can use the duplicated() method.

iris.duplicated()

	123 SepalLengthCm Numeric(7)	...	Abc Species Varchar(30)	123 occurrence Integer
1	3.3	...	Iris-setosa	51
2	4.3	...	Iris-virginica	50
3	4.9	...	Iris-setosa	3
4	5.5	...	Iris-versicolor	2
5	5.8	...	Iris-virginica	2
6	7.4	...	Iris-virginica	2

As you might expect, some flowers might share the exact same characteristics. But we have to be careful; this doesn’t mean that they are real duplicates. In this case, we don’t have to drop them.

That said, if we did want to drop these duplicates, we can do so with the drop_duplicates() method.

iris.drop_duplicates()

	123 SepalLengthCm Numeric(7) 100%	...	123 PetalWidthCm Numeric(7) 100%	Abc Species Varchar(30) 100%
1	7.7	...	2.2	Iris-virginica
2	5.7	...	0.4	Iris-setosa
3	6.7	...	1.7	Iris-versicolor
4	6.3	...	2.5	Iris-virginica
5	5.4	...	1.5	Iris-versicolor
6	5.5	...	1.1	Iris-versicolor
7	5.7	...	1.2	Iris-versicolor
8	6.1	...	1.4	Iris-versicolor
9	6.4	...	1.3	Iris-versicolor
10	7.1	...	2.1	Iris-virginica
11	4.9	...	0.2	Iris-setosa
12	7.0	...	1.4	Iris-versicolor
13	5.0	...	0.2	Iris-setosa
14	5.4	...	0.4	Iris-setosa
15	5.8	...	2.4	Iris-virginica
16	4.6	...	0.2	Iris-setosa
17	4.9	...	0.1	Iris-setosa
18	6.3	...	1.5	Iris-versicolor
19	4.8	...	0.1	Iris-setosa
20	5.4	...	0.4	Iris-setosa

Using this method will add an advanced analytical function to the SQL code generation which is quite expensive. You should only use this method after aggregating the data to avoid stacking heavy computations on top of each other.