Pandas is an open-source scientific computing package for Python programming language which provides high-performance, easy to use data structures and data analysis tools to work with data. Some of the domains where Pandas is used are Deep Learning, Computer Vision, Machine Learning, Image Processing, Data Analytics, Spreadsheet manipulation etc.
In this page, you will find the syntax and most common how to’s of Pandas in Python. This might be useful for python beginners to find syntax and code quickly online in a single page.
Contents
Update: As Python2 faces end of life, the below code only supports Python3.
Check pandas versioncode
1
2
import pandas as pd
print(pd.__version__)
1
'0.24.2'
Load toy dataset to work with pandascode
1
2
3
4
# please install scikit-learn - https://scikit-learn.org/ to use this dataset
from sklearn.datasets import load_breast_cancer
cancer = load_breast_cancer()
print(cancer.DESCR)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
Breast Cancer Wisconsin (Diagnostic) Database
=============================================
Notes
-----
Data Set Characteristics:
:Number of Instances: 569
:Number of Attributes: 30 numeric, predictive attributes and the class
:Attribute Information:
- radius (mean of distances from center to points on the perimeter)
- texture (standard deviation of gray-scale values)
- perimeter
- area
- smoothness (local variation in radius lengths)
- compactness (perimeter^2 / area - 1.0)
- concavity (severity of concave portions of the contour)
- concave points (number of concave portions of the contour)
- symmetry
- fractal dimension ("coastline approximation" - 1)
The mean, standard error, and "worst" or largest (mean of the three
largest values) of these features were computed for each image,
resulting in 30 features. For instance, field 3 is Mean Radius, field
13 is Radius SE, field 23 is Worst Radius.
- class:
- WDBC-Malignant
- WDBC-Benign
:Summary Statistics:
===================================== ====== ======
Min Max
===================================== ====== ======
radius (mean): 6.981 28.11
texture (mean): 9.71 39.28
perimeter (mean): 43.79 188.5
area (mean): 143.5 2501.0
smoothness (mean): 0.053 0.163
compactness (mean): 0.019 0.345
concavity (mean): 0.0 0.427
concave points (mean): 0.0 0.201
symmetry (mean): 0.106 0.304
fractal dimension (mean): 0.05 0.097
radius (standard error): 0.112 2.873
texture (standard error): 0.36 4.885
perimeter (standard error): 0.757 21.98
area (standard error): 6.802 542.2
smoothness (standard error): 0.002 0.031
compactness (standard error): 0.002 0.135
concavity (standard error): 0.0 0.396
concave points (standard error): 0.0 0.053
symmetry (standard error): 0.008 0.079
fractal dimension (standard error): 0.001 0.03
radius (worst): 7.93 36.04
texture (worst): 12.02 49.54
perimeter (worst): 50.41 251.2
area (worst): 185.2 4254.0
smoothness (worst): 0.071 0.223
compactness (worst): 0.027 1.058
concavity (worst): 0.0 1.252
concave points (worst): 0.0 0.291
symmetry (worst): 0.156 0.664
fractal dimension (worst): 0.055 0.208
===================================== ====== ======
:Missing Attribute Values: None
:Class Distribution: 212 - Malignant, 357 - Benign
:Creator: Dr. William H. Wolberg, W. Nick Street, Olvi L. Mangasarian
:Donor: Nick Street
:Date: November, 1995
This is a copy of UCI ML Breast Cancer Wisconsin (Diagnostic) datasets.
https://goo.gl/U2Uwz2
Features are computed from a digitized image of a fine needle
aspirate (FNA) of a breast mass. They describe
characteristics of the cell nuclei present in the image.
Separating plane described above was obtained using
Multisurface Method-Tree (MSM-T) [K. P. Bennett, "Decision Tree
Construction Via Linear Programming." Proceedings of the 4th
Midwest Artificial Intelligence and Cognitive Science Society,
pp. 97-101, 1992], a classification method which uses linear
programming to construct a decision tree. Relevant features
were selected using an exhaustive search in the space of 1-4
features and 1-3 separating planes.
The actual linear program used to obtain the separating plane
in the 3-dimensional space is that described in:
[K. P. Bennett and O. L. Mangasarian: "Robust Linear
Programming Discrimination of Two Linearly Inseparable Sets",
Optimization Methods and Software 1, 1992, 23-34].
This database is also available through the UW CS ftp server:
ftp ftp.cs.wisc.edu
cd math-prog/cpo-dataset/machine-learn/WDBC/
References
----------
- W.N. Street, W.H. Wolberg and O.L. Mangasarian. Nuclear feature extraction
for breast tumor diagnosis. IS&T/SPIE 1993 International Symposium on
Electronic Imaging: Science and Technology, volume 1905, pages 861-870,
San Jose, CA, 1993.
- O.L. Mangasarian, W.N. Street and W.H. Wolberg. Breast cancer diagnosis and
prognosis via linear programming. Operations Research, 43(4), pages 570-577,
July-August 1995.
- W.H. Wolberg, W.N. Street, and O.L. Mangasarian. Machine learning techniques
to diagnose breast cancer from fine-needle aspirates. Cancer Letters 77 (1994)
163-171.
How to create a DataFrame?code
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
X = cancer["data"]
y = np.expand_dims(cancer["target"], axis=1)
index = range(0, 569, 1)
columns = [ 'mean radius', 'mean texture', 'mean perimeter', 'mean area',
'mean smoothness', 'mean compactness', 'mean concavity',
'mean concave points', 'mean symmetry', 'mean fractal dimension',
'radius error', 'texture error', 'perimeter error', 'area error',
'smoothness error', 'compactness error', 'concavity error',
'concave points error', 'symmetry error', 'fractal dimension error',
'worst radius', 'worst texture', 'worst perimeter', 'worst area',
'worst smoothness', 'worst compactness', 'worst concavity',
'worst concave points', 'worst symmetry', 'worst fractal dimension',
'target' ]
cancerdf = pd.DataFrame(np.concatenate((X, y), axis=1), index=index, columns=columns)
print(cancerdf.shape)
1
(569, 31)
How to view head of a DataFrame?code
1
cancerdf.head()
1
2
3
4
5
6
7
8
mean radius mean texture mean perimeter ... worst symmetry worst fractal dimension target
0 17.99 10.38 122.80 ... 0.4601 0.11890 0.0
1 20.57 17.77 132.90 ... 0.2750 0.08902 0.0
2 19.69 21.25 130.00 ... 0.3613 0.08758 0.0
3 11.42 20.38 77.58 ... 0.6638 0.17300 0.0
4 20.29 14.34 135.10 ... 0.2364 0.07678 0.0
[5 rows x 31 columns]
How to count unique values in a DataFrame column?code
1
2
3
4
5
6
count_malignant = cancerdf["target"].loc[cancerdf["target"]==0.0].count()
count_benign = cancerdf["target"].loc[cancerdf["target"]==1.0].count()
# create a pandas series
target = pd.Series([count_malignant, count_benign], index=["malignant", "benign"])
print(target)
1
2
3
malignant 212
benign 357
dtype: int64
How to split a dataframe?code
1
2
3
4
X = cancerdf.iloc[:, :cancerdf.shape[1]-1]
y = cancerdf.iloc[:, cancerdf.shape[1]-1]
print(X.shape)
print(y.shape)
1
2
(569, 30)
(569,)
References
In case if you found something useful to add to this article or you found a bug in the code or would like to improve some points mentioned, feel free to write it down in the comments. Hope you found something useful here.