Data World Blog

abs()  function computes the absolute value of x, while  sqrt()  functions computes the square root of x. the only parameter for these functions is  x , which is the value to compute. abs ( 10 ) ## [1] 10 abs ( - 10 ) ## [1] 10 sqrt ( 10 ) ## [1] 3.162278 sqrt ( - 10 ) ## Warning in sqrt(-10): NaNs produced ## [1] NaN sqrt ( abs ( - 10 ) ) ## [1] 3.162278 plot ( 15 : - 15 , sqrt ( abs ( 15 : - 15 ) ) , col = "orange" ) lines ( spline ( 15 : - 15 , sqrt ( abs ( 15 : - 15 ) ) ) , col = "gold" )

duplicated()  function is a general function that determines which elements are duplicated, it returns a logical vector: The parameters of the function are:  x : vector, array or data frame   fromLast :logical indicating if duplication should be considered from the last x = c ( 5 : 1 , 5 : 1 , 5 ) x ## [1] 5 4 3 2 1 5 4 3 2 1 5 duplicated ( x ) ## [1] FALSE FALSE FALSE FALSE FALSE TRUE TRUE TRUE TRUE TRUE TRUE duplicated ( x , fromLast = TRUE ) ## [1] TRUE TRUE TRUE TRUE TRUE TRUE FALSE FALSE FALSE FALSE FALSE ## extract duplicated elements, those elements that duplicated(x) == TRUE, may be repeted elements: x [ duplicated ( x ) ] ## [1] 5 4 3 2 1 5 ## extract unique elements x [ ! duplicated ( x ) ] ## [1] 5 4 3 2 1 ## extract unique elements starting from the righmost value (different order): x [ ! duplicated ( x , fromLast = TRUE ) ] ## [1] 4 3 2 1 5 #duplicated using a data frmae duplicated ( iris ) ## [1] FALSE FALS...

Create a function in R: Function  function()  allows us to create specific functions. Between parenthesis we put the name of the parameters we want to create to be used in our function.     Function(parameter1, parameter2, ...){         statements         return(object) } NameFunction0 = function ( x , y ) { return ( ( x + y ) / 2 ) } NameFunction0 ( 4 , 5 ) ## [1] 4.5 If we want use a parameter that may or may not be specified we use  parameter = NULL : NameFunction1 = function ( x , y = NULL ) { if ( ! is.null ( y ) ) x = x + y return ( x ) } NameFunction1 ( 5 , 10 ) #with 2 paramers (x,y) ## [1] 15 NameFunction1 ( 5 ) #with only only parameter (x) ## [1] 5 Initial Data Analysis Functions Here we have created some basic functions that can be used for initial data analysis of our data: INLIERS  returns the values of a vector that are between the vales ...