.Rhistory

find.package("devtools")
install.packages("devtools")
library(devtools)
find_rtools()
library(KernSmooth)
data<-read.csv("hw1_data")
data<-read.csv("hw1_data.csv")
setwd("~/DataSci/datasciencecoursera")
data<-read.csv("hw1_data.csv")
data[nrow=2]
data[c(1:2),]
rownum(data)
rowcount(data)
nrow
nrow(data)
data[c(nrow(data)-1,nrow(data)),]
data[47,"Ozone"]
data[47,c("Ozone")]
data[,"Ozon".isNa()]
data[,"Ozone".isNa()]
data[,"Ozone"]
data[,"Ozone"].isNa()
data[,data[,"Ozone"].isNa()]
is.na(data$Ozone)
table(factor(is.na(c(data$Ozone))))
mean(data$Ozone[!is.na(data$Ozone)])
good <- complete.cases(data$Ozone, data$Solar.R, data$Temp)
mean(data$Solar.R[good & data$Ozone > 31 & data$Temp > 90])
good <- complete.cases(data$Month, data$Temp)
mean(data$Temp[good & data$Month == 6])
max(data$Ozone[data$Month==5 & !is.na(data$Ozone)])