R Beginners Functions

R is another open source programmer language, inspired from S language which was written for Statistician who wanted to do Data Analytics and Data Science.

Here are some beginner functions you can use to write start working with.

  • getwd() to check there current working directory

  • setwd("~/Desktop/") to change the current working directory location

  • dir() to check the files in that directory.

  • c or array fns to create an array

  • rbind to combine two arrays

  • sort to sort values

  • seq to generate numbers in a range(range fns in Python)

  • which.max returns the index of the max element in the array

  • data.frame to create a data frame from arrays

  • read.csv to create a data frame from csv

  • write.csv(WHO_Europe, "WHO_Europe.csv”) to save the file

  • match is like a counting no.of times a value occurred in a column

  • as.numeric to convert boolean/logical operator values to numeric

some constants

  • NA : Not Available (i.e. missing values)

  • NaN : Not a Number (e.g. 0/0)

  • Inf: Infinity

  • -Inf : Minus Infinity.

dataframe

  • names to print all the column names in a data frame

  • $ to check a data frame each column’s values

  • dim to check the shape of the data frame

  • str to check the structure/type of object/variable

  • summary to check summary of data frame

  • subset to filter the required data.

  • table is like summary of a categorical variables

  • tapply(WHO$Over60, WHO$Region, max) is like pivot

  • tapply(WHO$LiteracyRate, WHO$Region, max, na.rm=TRUE) excluding the NA’s

Check/remove Locals variables

  • ls() to check all local variables

  • rm(..) to remove variables

__Plotting __

  • hist to do histogram plots

  • plot for scatter plots/ linear plots

  • boxplot(WHO$LifeExpectancy ~ WHO$Region) to box plot Life Expectancy for each region

    • internal optional labels are xlab, ylab, name

Date/Format

  • as.Date(strptime(, "%m/%d/%y %H:%M”)) to convert string into Date Type

  • format to convert strings into string

BUILT-IN FUNCTION

  • http://www.statmethods.net/management/functions.html

EXAMPLES:

  • https://en.wikibooks.org/wiki/R_Programming/Sample_Session

MAP, REDUCE, FILTER, FIND, NEGATE:

  • http://www.johnmyleswhite.com/notebook/2010/09/23/higher-order-functions-in-r/

Sample Data Files:

  • https://d37djvu3ytnwxt.cloudfront.net/assets/courseware/v1/ccdc87b80d92a9c24de2f04daec5bb58/asset-v1:MITx+15.071x_3+1T2016+type@asset+block/WHO.csv

  • https://d37djvu3ytnwxt.cloudfront.net/assets/courseware/v1/3ef78a720083c74cd2649289a475158d/asset-v1:MITx+15.071x_3+1T2016+type@asset+block/USDA.csv