course work and codes from online lectures
week-2 module for R studio workshop. Programming with R. If else statment use, and for loop, While loop statments with example. defining and using functions. Helps and makes easy to manipulate data after defining fucntions. created various function of addition and calcualting means, above, STDEV, lexical scoping and dynamic scoping- defines how variables are looked up, they use different strategies, lexical based on how variables are looked up and dynamic based on fucntions.
weeek -3 Loop functions and debugging in R studio. lapply- workhorse function. sapply- variant of lapply, simplify the result of lapply gives a line of result, insted of list. apply- loop used to evaluate function over array. mostly used to matrix. mapply- (multivariate function of sapply)apply parlell functions overall, insted of elements of single objects. tapply- used to apply function over subsets of a vector. Debugging. message - a generic notification/diagnostic message. warning- something is wrong but not fatel. error-An indication of fatal problem occured. condition- a generic indication of something wrong can occur. the basic primary tools for debugging in R. traceback- prints out the function after an error occurs and does nothing if there is no error.(tells where error occurs) debug- flags a function for debug mode. allows you to step throughexecution of a function one by one line. browser-suspends the function execution and puts function in debug mode trace-allows you to insert debugging code into a fucntion. recover- allows to modify error behaviour by stopping the execution of function at error.
Str (structure) function- takes an R object- compactly dispaly inner function. alternative summary one line output.
simulation -generating random numbers probability distribution functions usually have 4 functions associated wuth them. those prefixed with. d -density r -randon number generation p - cumulative distribution q - quantile function.