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Machine Learning with R Cookbook, Second Edition

You're reading from   Machine Learning with R Cookbook, Second Edition Analyze data and build predictive models

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Product type Paperback
Published in Oct 2017
Publisher Packt
ISBN-13 9781787284395
Length 572 pages
Edition 2nd Edition
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Authors (2):
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Ashish Bhatia Ashish Bhatia
Author Profile Icon Ashish Bhatia
Ashish Bhatia
Yu-Wei, Chiu (David Chiu) Yu-Wei, Chiu (David Chiu)
Author Profile Icon Yu-Wei, Chiu (David Chiu)
Yu-Wei, Chiu (David Chiu)
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Table of Contents (15) Chapters Close

Preface 1. Practical Machine Learning with R FREE CHAPTER 2. Data Exploration with Air Quality Datasets 3. Analyzing Time Series Data 4. R and Statistics 5. Understanding Regression Analysis 6. Survival Analysis 7. Classification 1 - Tree, Lazy, and Probabilistic 8. Classification 2 - Neural Network and SVM 9. Model Evaluation 10. Ensemble Learning 11. Clustering 12. Association Analysis and Sequence Mining 13. Dimension Reduction 14. Big Data Analysis (R and Hadoop)

Understanding data sampling in R


Sampling is a method to select a subset of data from a statistical population, which can use the characteristics of the population to estimate the whole population. The following recipe will demonstrate how to generate samples in R.

Getting ready

Make sure that you have an R working environment for the following recipe.

How to do it...

Perform the following steps to understand data sampling in R:

  1. To generate random samples of a given population, the user can simply use the sample function:
> sample(1:10)
  1. To specify the number of items returned, the user can set the assigned value to the size argument:
> sample(1:10, size = 5)
  1. Moreover, the sample can also generate Bernoulli trials by specifying replace = TRUE (default is FALSE):
> sample(c(0,1), 10, replace = TRUE)
  1. If we want to do a coin flipping trail, where the outcome is Head or Tail, we can use:
  > outcome <- c("Head","Tail")  > sample(outcome, size=1)
  1. To generate result for 100 times, we can use...
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