In UBC-MDS/rsketball: Scrape data from ESPN NBA and show summary statistics/visualisations

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rsketball

Analysis of NBA players from 2001/02 to 2018/19 seasons using ESPN NBA

This package is designated for all NBA enthusiasts! The rsketball package works to scrape online tabular data from the ESPN NBA website into a csv file. It also includes various functions to create graphs and statistical analysis for your interest (such as boxplots, player rankings by stats, and a summary statistics table).

An example of the ESPN NBA 2018/19 Regular season player stats can be found in this EPSN NBA url

This project is proudly created by:

• Carlina Kim
• Andres Pitta
• V Anand Shankar
• Kenneth Foo

Functions

nba_scraper

• Scrapes data from ESPN NBA data into a csv file. User can specify the year of the season (2001 to 2019 at the moment) and the season type ("regular" or "postseason").

nba_boxplot

• Creates a boxplot of the categorical variable of interest (TEAM or POS) on the y-axis and the numerical statistic of interest on the x-axis.

nba_ranking

• Generates a ranking visualization based on the numerical statistic of interest column of a dataset.

nba_team_stats

• Generate summary stats for NBA players. The function provides descriptive (mean, median, 25%, and 75% quantiles) team statistics of NBA data. It also comes with added functionalities for player position grouping per team too.

For a more detailed understanding of the functions and their use cases, please refer to the package vignette.

Installation

rsketball is still in project development. We estimate that by end March 2020, one can install the released version of rsketball from CRAN.

Package installation in R:

install.packages("rsketball")

And the development version from Github with:

install.packages("devtools")
devtools::install_github("UBC-MDS/rsketball")

Required Preparation for Scraping with nba_scraper()

The rsketball::nba_scraper is based on Selenium (or specifically RSelenium) which enables automated web browsing through "drivers". To use it, please ensure that Docker is installed.

For installation instructions, please follow the guide to Docker installation based on your OS type. Docker will be used to pull the relevant Chromedriver image that when executed as containers, will serve as the "driver" for Selenium.

The following steps are required only for the nba_scraper function. If you already have the scraped data file and wish to use the other functions (nba_boxplot, nba_rank, nbastats), there is no need to proceed with these steps.

Step 1 (Command line/Terminal): Preparation of Docker container

Pull the docker image with the following code in Terminal. We will stick to Chrome since it seems compatible with Windows while Firefox is not.

docker pull selenium/standalone-chrome

Critical step about setting ports and memory allocation:

We need to set up the Docker container default port 4444 to our computer host port 4445. Keep this port number as inputs for the nba_scraper function. We will also allocate 2GB of virtual memory for the container to scrape effectively.

Run the following code in Terminal:

docker run -d -p 4445:4444 --shm-size 2g selenium/standalone-chrome

Verify that the docker container is in operation by running the following code in Terminal:

docker ps 

Step 2 (R/RStudio): Scraping with nba_scraper

Now that the container is running with the allocated memory and assigned port, we can proceed with testing

library(rsketball)

# Scrape postseason season 2017/18 while saving to a local csv file.
nba_2017_playoffs <- nba_scraper(season_year = 2017, 
                                 season_type = "postseason",
                                 port=4445L, # Port number as per Docker container setup
                                 csv_path = "nba_2017_playoffs.csv")

If everything was executed as intended, you should obtain a csv file called "nba_2017_playoffs.csv" containing the scraped data, and a tibble in your R environment named "nba_2017_playoffs". With the tibble, you can use the other rsketball functions for your analysis.

Step 3 (Command line/Terminal): Termination of Docker Container

After test scraping is completed, we can shut down the Docker Container instance. This will also ensure that your computer memory/resources are restored.

docker stop $(docker ps -q)

If you wish to, you can also remove the Docker image from your computer, where "" represents the id of your Docker image.

docker image rm <image_id>

Usage Examples

Once the Docker steps are setup with the relevant container running as mentioned in the Preparation steps above, you can start up R.

nba_scraper()

To load the package:

library(rsketball)

nba_scraper() will help you create the dataframe of the NBA season of interest to conduct further analysis using the functions below. The following examples is for scraping the playoffs (postseason) season in 2017/18 while saving to a local csv file.

nba_2017 <- nba_scraper(2017, season_type = "postseason",
                        port=4445L, # Port number as per Docker container setup
                        csv_path = "nba_2017_playoffs.csv")

Effective usage of the rest of the functions in rsketball may require certain knowledge of the available columns in the scraped data. For more context on the column names of the scraped data set, please refer to the dataset description file. This will help the user better understand what columns are included in the scraped data, as well as what they represent.

For the illustration of the other functions, let's create a toy dataset with similar properties as the scraped data from ESPN NBA.

nba_data <- tibble::tibble(NAME = c("James", "Steph", "Bosh", "Klay", "Kobe"),
                    TEAM = c("MIA","GS","MIA","GS","LAL"),
                    POS = c("SF", "PG", "C", "SG", "SG"),
                    PTS = c(5,4,3,2,10),
                    TO = c(1,2,3,4,3),
                    `3PA` = c(10, 20, 30, 40, 50),
                    `FT%` = c(50, 60, 70, 80, 90))

nba_boxplot()

To further compare the different statistics (scoring, steals, rebounds, etc) across different teams in combination with different player positions, you can use nba_boxplot().

To look at the distribution of Free Throws Percentage or 'FT%' (which is a numerical column) for specific teams (must pass in a list).

Important: Since the column id (FT%) has a "%" character in it, we must ensure that the input for stats_column is formatted with backticks as shown:

nba_boxplot(nba_data, 
            team_or_position= "team", 
            grouping_list = c("MIA", "GS"), 
            stats_column = `FT%`) # Formatted with backticks.

nba_ranking()

The nba_ranking() function creates a visualization showing the rankings of a category with a statistic of interest.

In the this example, we rank the top 3 players (NAME) based on their number of Three Points Attempts (3PA) made in a descending order.

Important: Since the column id starts with a number 3, we must ensure that the input for stats_column is formatted with backticks as shown:

# Find top 3 players for 3 Point Attempts (3PA) where higher is better
nba_ranking(nba_data,
            column = NAME,
            by = `3PA`, # Formatted with backticks.
            top = 3,
            descending = TRUE,
            FUN = mean)

nba_team_stats()

The nba_team_stats() function finds statistics of mean, median, 25%, and 75% quantiles. This function is primarily focused on team, and allows for further grouping by player position per team.

In this example, we obtain the descriptive statistics of relevant numeric columns (PTS and TO) for specific teams (GS and LAL) with added grouping of their player positions (C and PG).

# Find specific stats (PTS, TO) for specific teams (GS, LAL) for specific positions (PG, SG)
nba_team_stats(nba_data, 
               stats_filter = c("PTS","TO"),
               teams_filter = c("GS","LAL"), 
               positions_filter = c("SG","PG"))

For a more detailed understanding of the functions and their use cases, please refer to the package vignette.

Testing

To do testing of the package functions, please refer to the instructions found in the README.md located at the testing subdirectory folder.

Dependencies

dplyr>=0.8.3

forcats>=0.5.0

ggplot2>=3.2.1

magrittr>=1.5

readr>=1.3.1

rlang>=0.4.2

rvest>=0.3.4

scales>=1.1.0

tibble>=2.1.3

RSelenium>=1.7.7

R Ecosystem

This rsketball package aims to further gain understanding of ESPN NBA data and does not have a specific fit to the R ecosystem. There are currently some other library packages such as nbastatR that take data from other sources (NBA Stats API, Basketball Insiders, Basketball-Reference, HoopsHype, and RealGM), but no package that we currently know of takes data from ESPN NBA specifically.

UBC-MDS/rsketball documentation built on April 1, 2020, 4:37 a.m.