R

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: