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Numerical Computing with Python

You're reading from   Numerical Computing with Python Harness the power of Python to analyze and find hidden patterns in the data

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Product type Course
Published in Dec 2018
Publisher Packt
ISBN-13 9781789953633
Length 682 pages
Edition 1st Edition
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Authors (5):
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Pratap Dangeti Pratap Dangeti
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Pratap Dangeti
Theodore Petrou Theodore Petrou
Author Profile Icon Theodore Petrou
Theodore Petrou
Allen Yu Allen Yu
Author Profile Icon Allen Yu
Allen Yu
Aldrin Yim Aldrin Yim
Author Profile Icon Aldrin Yim
Aldrin Yim
Claire Chung Claire Chung
Author Profile Icon Claire Chung
Claire Chung
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Toc

Table of Contents (21) Chapters Close

Title Page
Contributors
About Packt
Preface
1. Journey from Statistics to Machine Learning FREE CHAPTER 2. Tree-Based Machine Learning Models 3. K-Nearest Neighbors and Naive Bayes 4. Unsupervised Learning 5. Reinforcement Learning 6. Hello Plotting World! 7. Visualizing Online Data 8. Visualizing Multivariate Data 9. Adding Interactivity and Animating Plots 10. Selecting Subsets of Data 11. Boolean Indexing 12. Index Alignment 13. Grouping for Aggregation, Filtration, and Transformation 14. Restructuring Data into a Tidy Form 15. Combining Pandas Objects 1. Other Books You May Enjoy Index

Speeding up scalar selection


Both the .iloc and .loc indexers are capable of selecting a single element, a scalar value, from a Series or DataFrame. However, there exist the indexers, .iat and .at, which respectively achieve the same thing at faster speeds. Like .iloc, the .iat indexer uses integer location to make its selection and must be passed two integers separated by a comma. Similar to .loc, the .at index uses labels to make its selection and must be passed an index and column label separated by a comma.

 

Getting ready

This recipe is valuable if computational time is of utmost importance. It shows the performance improvement of .iat and .at over .iloc and .loc when using scalar selection.

How to do it...

  1. Read in the college scoreboard dataset with the institution name as the index. Pass a college name and column name to.loc in order to select a scalar value:
>>> college = pd.read_csv('data/college.csv', index_col='INSTNM')
>>> cn = 'Texas A & M University-College...
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