**R programming Language****Python****programming language**Model Building is similar to Python Model Building is similar to R. Model Interpretability is good Model Interpretability is not good Production is not better than Python. Production is good R has good community support over Python. Community Support is not better than R Data Science Libraries are same as Python. Data Science Libraries are same as R. R has good data visualizations libraries and tools Data visualization is not better than R R has a steep learning curve. Learning Curve in Python is easier than learning R.

- R provides to import data in R language. To begin with the R commander GUI, user should type the commands in the command Rcmdr into the console. Data can be imported in R language in 3 ways such as:
- Select the data set in the dialog box or enter the name of the data set as required.
- Data is entered directly using the editor of R Commander via Data->New Data Set. This works good only when the data set is not too large.
- Data can also be imported from a URL or from plain text file (ASCII), or from any statistical package or from the clipboard.

- Combine the data, code and analysis results in a single document using knitr for Reproducible research done. Helps to verify the findings, add to them and engage in conversations. Reproducible research makes it easy to redo the experiments by inserting new data values and applying it to different various problems.

**library()****require()**Library () function gives an error message display, if the desired package cannot be loaded. Require () function is used inside function and throws a warning messages whenever a particular package is not Found It loads the packages whether it is already loaded or not, It just checks that it is loaded, or loads it if it isn’t (use in functions that rely on a certain package). The documentation explicitly states that neither function will reload an already loaded package. `Consider a related program for the above differentiation.`

if(!require(package, character.only=T, quietly=T)) {

install.packages (package)

library(package, character.only=T)

}

For multiple packages you can use

for(package in c(”, ”)) {

if(!require(package, character.only=T, quietly=T)) {

install.packages (package)

library(package, character.only=T)

}

}

- R is a programming language which is used for developing statistical software and data analysis. It is being increasingly deployed for machine learning applications as well.

- By using # at the starting of the line of code like #division commands are written.

- It is used to determine that the means of two groups are equal or not by using t.test() function.

- The disadvantages are:-
- Lack of standard GUI
- Not good for big data.
- Does not provide spreadsheet view of data.

- with() function applies an expression to a dataset.
#with(data,expression)

- By() function applies a function t each level of a factors.
#by(data,factorlist,function)

- In R missing values are represented by NA which should be in capital letters.

- Subset() is used to select the variables and observations and sample() function is used to generate a random sample of the size n from a dataset.

- Transpose is used for reshaping of the data which is used for analysis. Transpose is performed by t() function.

- The advantages are:-
- It is used for managing and manipulating of data.
- No license restrictions
- Free and open source software.
- Graphical capabilities of R are good.
- Runs on many Operating system and different hardware and also run on 32 & 64 bit processors etc.

- For adding two datasets rbind() function is used but the column of two datasets must be same.
Syntax: rbind(x1,x2……) where x1,x2: vector, matrix, data frames.

- Cor-relations is produced by cor() and covariances is produced by cov() function.

- Dataframe can contain different type of data but matrix can contain only similar type of data.

- lapply is used to show the output in the form of list whereas sapply is used to show the output in the form of vector or data frame

- Seq(4) means vector from 1 to 4 (c(1,2,3,4)) whereas seq_along(4) means a vector of the length(4) or 1(c(1)).

- rcmdr command is used to start the R commander GUI.

- In 32 bit system memory limit is 3Gb but most versions limited to 2Gb and in 64 bit system memory limit is 8Tb.

- There are 5 data structure in R i.e. vector, matrix, array which are of homogenous type and other two are list and data frame which are heterogeneous.

- There are two methods that is collapsing data by using one or more BY variable and other is aggregate() function in which BY variable should be in list.

- There are 5 types of sorting algorithms are used which are:-
- Bubble Sort
- Selection Sort
- Merge Sort
- Quick Sort
- Bucket Sort

- For creating new variable assignment operator ‘<-’ is used

For e.g. mydata x1 + mydata$x2s u m < − m y d a t a

- Packages are the collections of data, R functions and compiled code in a well-defined format and these packages are stored in library. One of the strengths of R is the user-written function in R language.

- Workspace is the current R working environment which includes any user defined objects like vector, lists etc.

- Merge()function is used to merge two data frames

Eg. Sum<-merge(data frame1,data frame 2,by=’ID’)

- rbind() function is used to merge two data frames vertically.

Eg. Sum<- rbind(data frame1,data frame 2)

- It is used for experimental design .It is used to determine the effect of given sample size.

- Pwr package is used for power analysis in R.

- There are many ways to export the data into another formats like SPSS, SAS , Stata , Excel Spreadsheet.

- For excel xlsReadWrite package is used and for sas,spss ,stata foreign package is implemented.

- In R NaN is used to represent impossible values.

- Save command is used for storing R objects into a file.

Syntax: >save(z,file=”z.Rdata”)

- load command is used for storing R objects from a file.

Syntax: >load(”z.Rdata”)

- Coin package is used to achieve the re randomization or permutation based statistical tests.

- order() function is used to perform the sorting.

- IOS-6.1.3

- The event will be dispatched to your delegate for processing.

- The app specific objects are Data model objects that store app’s contents.

- UIWindow object coordinates the one or more views presenting on the screen.

- UIView Controller class.

- Using axes() function custom axes are created.

- abline() function is add the reference line to a graph.

Syntax:- abline(h=yvalues, v=xvalues)

- vcd package provides different methods for visualizing multivariate categorical data.

- GGobi is an open source program for visualization for exploring high dimensional typed data.

- It is a package which provide bar plots, mosaic plots, box plots, parallel plots, scatter plots and histograms.

- lattice package is to improve on base R graphics by giving better defaults and it have the ability to easily display multivariate relationships.

- It is used to provide the maximum likelihood fitting of univariate distributions. It is defined under the MASS package.

- Data structures are vectors, arrays, data frames and matrices.