Ujjwal Karn's blog

k-means clustering aims to partition n observations into k clusters in which each observation belongs to the cluster with the nearest mean, serving as a prototype of the cluster. I have provided below the R code to get started with k-means clustering in R. The dataset can be downloaded from here.    

Logistic regression, or logit regression is a regression model where the dependent variable is categorical. I have provided code below to perform end-to-end logistic regression in R including data preprocessing, training and evaluation. The dataset used can be downloaded from here.

Listed below are codes for some data frame operations that are good to have at your fingertips: Create an empty data.frame Sort a dataframe by column(s) Merge/Join data frames (inner, outer, left, right) Drop data frame columns by name Remove rows with NAs in data.frame Quickly reading very large tables as dataframes in R Drop … More Codes for common Data Frame operations in R

I have listed some useful functions below: with() The with( ) function applys an expression to a dataset. It is similar to DATA= in SAS. # with(data, expression) # example applying a t-test to a data frame mydata with(mydata, t.test(y ~ group)) Please look at other examples here and here. by() The by( ) function … More Useful functions in R

Given below is a list of useful cheatsheets for R: Data Wrangling in R ggplot2 Cheatsheet Shiny Cheatsheet devtools Cheatsheet markdown Cheatsheet,  reference Data Exploration Cheatsheet  

Originally posted on Learning R:
The data visualization package lattice is part of the base R distribution, and like ggplot2 is built on Grid graphics engine. Deepayan Sarkar’s (the developer of lattice) book Lattice: Multivariate Data Visualization with R gives a detailed overview of how the package works. All the figures and code used to…