Quiz3.R

Quiz3.R

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+
+dir<-"C:\\Users\\Gemma\\Dropbox\\Coursera\\GettingAndCleaningData\\Week3"
+setwd(dir)
+getwd()
+if (!file.exists(dir)){
+        dir.create(dir)
+}
+
+#############
+#QUESTION 1
+#############
+fileUrl<-"https://d396qusza40orc.cloudfront.net/getdata%2Fdata%2Fss06hid.csv"
+download.file(fileUrl, destfile = "Idaho.csv")
+idaho<-read.csv("Idaho.csv")
+dim(idaho)
+str(idaho)
+agricultureLogical<- idaho$ACR==3 & idaho$AGS==6
+?which
+which(agricultureLogical)
+
+#############
+#QUESTION 2
+#############
+install.packages("jpeg")
+library(jpeg)
+fileUrl<-"https://d396qusza40orc.cloudfront.net/getdata%2Fjeff.jpg"
+?download.file
+download.file(fileUrl,destfile = "jeffJPEG.jpg", mode="wb")
+img <- readJPEG("jeffPEG.jpg", native = TRUE)
+quantile(img, probs = c(0.3,0.8))
+
+#############
+#QUESTION 3
+#############
+library(dplyr)
+dfGDP<-read.csv("https://d396qusza40orc.cloudfront.net/getdata%2Fdata%2FGDP.csv",stringsAsFactors = FALSE,skip = 5, header = F)
+dfEducation<-read.csv("https://d396qusza40orc.cloudfront.net/getdata%2Fdata%2FEDSTATS_Country.csv",stringsAsFactors = FALSE)
+str(dfGDP)
+str(dfEducation)
+tblGDP<-tbl_df(dfGDP)
+tblEducation<-tbl_df(dfEducation)
+rm(dfGDP)
+rm(dfEducation)
+?bind_rows
+?merge
+?join
+mergeData<-merge(tblGDP,tblEducation,by.x="V1",by.y="CountryCode")
+mergeData<-inner_join(tblEducation,tblGDP,by=c("CountryCode" = "V1"))
+mergeData<-filter(mergeData, V2!="")
+str(mergeData)
+mergeData<-arrange(mergeData,desc(as.numeric(V2)))
+mergeData[13,"Long.Name"]
+summarise(mergeData, count=n())
+
+#############
+#QUESTION 4
+#############
+str(mergeData)
+mergeData<-mutate(mergeData, Income.Group= factor(Income.Group), V2=as.numeric(V2))
+levels(mergeData$Income.Group)
+by_IncomeGroup<-group_by(mergeData,Income.Group)
+summarise(by_IncomeGroup, mean(V2,na.rm=T))
+
+#############
+#QUESTION 5
+#############
+
+?quantile
+mergeData<-mutate(mergeData, quantile_rankGDP=cut(V2,breaks = quantile(V2, seq(0, 1, 0.2))))
+mergeData %>%
+        select(Income.Group,quantile_rankGDP)%>%
+        filter(Income.Group=="Lower middle income", quantile_rankGDP=="(1,38.6]")%>%
+        summarise(count=n())%>%
+        print
+