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# Dmitry Grapovdgrapov

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Created May 22, 2019
Data Science Exercise
View gist:d15aedea295f32fa43d76b0a864c577b
 DATA SCIENCE EXERCISE The following challenge requires the beer reviews data set called beer_reviews.csv. This data set can be downloaded from the following site: https://data.world/socialmediadata/beeradvocate . Note you can create a free temporary account to download this .csv. Questions to answer using this data: Which brewery produces the strongest beers by ABV%? If you had to pick 3 beers to recommend using only this data, which would you pick? Which of the factors (aroma, taste, appearance, palette) are most important in determining the overall quality of a beer? Additional math/coding question unrelated to the data:
Created Apr 6, 2018
Deep error
View replace_in.R
 > in Error: unexpected 'in' in "in"
Created Mar 24, 2018
basic principal components analysis and visualization in R
View pca.R
 # Basic PCA example # use www.createdatasol.com for # an advanced user interface #required packages for plotting library(ggplot2) library(ggrepel) #load data data<-read.csv('~/Sampledata.csv',
Created Feb 2, 2018
Example of a shiny app with data upload and different plot options
View example.R
 #initialize library(shiny) library(ggplot2) library(purrr) library(dplyr) #example data data(iris)
Created Jan 10, 2018
fast (?) implementations of tanimoto distance calculations
View tanimoto.R
 #' @title fast_tanimoto #' @param mat matrix or data frame of numeric values #' @param output 'matrix' (default) or 'edge list' (non-redundant and undirected) #' @param progress TRUE, show progress #' @imports reshape2 fast_tanimoto<-function(mat,output='matrix',progress=TRUE){ mat[is.na(mat)]<-0 #scoring function score<-function(x){sum(x==2)/sum(x>0)}
Last active Jun 19, 2019
ggplot2 to plotly to shiny to box/lasso select to DT
View plotly_select_DT.R
 #plotly box or lasso select linked to # DT data table # using Wage data # the out group: is sex:Male, region:Middle Atlantic + library(ggplot2) library(plotly) library(dplyr) library(ISLR)
Last active Jul 18, 2019
Self-organizing map (SOM) example in R
View SOM example.R
 #SOM example using wines data set library(kohonen) data(wines) set.seed(7) #create SOM grid sommap <- som(scale(wines), grid = somgrid(2, 2, "hexagonal")) ## use hierarchical clustering to cluster the codebook vectors groups<-3
Last active Sep 21, 2015
Convert adjacency (or other) matrix to edge list
View example.R
 library(reshape2) gen.mat.to.edge.list<-function(mat,symmetric=TRUE,diagonal=FALSE,text=FALSE){ #create edge list from matrix # if symmetric duplicates are removed mat<-as.matrix(mat) id<-is.na(mat) # used to allow missing mat[id]<-"nna" if(symmetric){mat[lower.tri(mat)]<-"na"} # use to allow missing values if(!diagonal){diag(mat)<-"na"}
Created Aug 21, 2015
Testing RECA: Relevant Component Analysis for Supervised Distance Metric Learning
View RECA_test.R
 #R code, testing RECA with the iris data library(RECA) #test data data(iris) x<-iris[,-5] y<-iris\$Species #similar groups (species) in each chunk (n=3) chunksvec<-as.numeric(y)
Last active Aug 29, 2015