# Articles by George Pipis

### Permutations in R

September 18, 2020 |

During the interview process for Data Science positions, it is likely to be asked to calculate Combinations or Permutations. Today ... Read morePermutations in R [Read more...]

### Covid19: Correlation Between Confirmed Cases and Deaths

September 6, 2020 |

What is the daily correlation of Confirmed versus Death Cases in Covid-19. In other words, the people who have passed ... Read moreCovid19: Correlation Between Confirmed Cases and Deaths

### How to Backtest your Crypto Trading Strategies in R

September 4, 2020 |

Few words about Trading Strategies One of the biggest challenges is to predict the Market. Many people have developed their ... Read moreHow to Backtest your Crypto Trading Strategies in R [Read more...]

### Interview questions about Stats and Probabilities

September 3, 2020 |

For Data Science positions, during the interview process, is common to ask questions about Statistics and Probabilities. We will provide ... Read moreInterview questions about Stats and Probabilities [Read more...]

### Avoid apply() function in large datasets

September 3, 2020 |

When we are dealing with large datasets and there is a need to calculate some values like the row/column min/max/rank/mean ... Read moreAvoid apply() function in large datasets

### R Exercises – Interview Questions (Stats and Simulation)

August 18, 2020 |

For Data Science positions that require some knowledge of Statistics and Programming skills, is common to ask questions like those ... Read moreR Exercises – Interview Questions (Stats and Simulation) [Read more...]

### How to get Cryptocurrency prices in R

August 7, 2020 |

Today, we will show how you can easily get the Cryptocurrency Prices using R. We will work with the crypto ... Read moreHow to get Cryptocurrency prices in R [Read more...]

### How to Apply Text Distances and Fuzzy Joins

May 25, 2020 |

Edit Distance for measuring the Text Distance Today we will talk about text similarities and how we can “calculate” a ... Read moreHow to Apply Text Distances and Fuzzy Joins [Read more...]

### How to build Stacked Ensemble Models in R

May 21, 2020 |

At this post, we will show you how you easily apply Stacked Ensemble Models in R using the H2O package. ... Read moreHow to build Stacked Ensemble Models in R

### How to determine the number of Clusters for K-Means in R

May 17, 2020 |

We will work with the Breast Cancer Wisconsin dataset, where we will apply the K-Means algorithm to the individual’s features ignoring the ... Read moreHow to determine the number of Clusters for K-Means in R

### R: How To Assign Values Based On Multiple Conditions Of Different Columns

May 12, 2020 |

In the previous post, we showed how we can assign values in Pandas Data Frames based on multiple conditions of ... Read moreR: How To Assign Values Based On Multiple Conditions Of Different Columns

### How to Impute Missing Values in R

April 18, 2020 |

In the real data world, it is quite common to deal with Missing Values (known as NAs). Sometimes, there is ... Read moreHow to Impute Missing Values in R [Read more...]

### Web Scraping worldometers for Coronavirus

April 12, 2020 |

One of the most popular web pages about Covid-19 is the worldometers which provides a detailed report about Coronavirus cases ... Read moreWeb Scraping worldometers for Coronavirus [Read more...]

### Report Coronavirus (COVID-19) in R

March 8, 2020 |

This post is about COVID-19 and we will an example of how you can get the data of the daily ... Read moreReport Coronavirus (COVID-19) in R