#Creare data.frame noi
Female <- data.frame("V1"=c(40,42,50), "V2"=c(0,2,3))
Male <- data.frame("V1"=c(60,40), "V2"=c(3,2))
People <- rbind(Female,Male)

#Import csv Excercitiul 2
setwd("d:\\MASTER\\Introducere in R\\R\\")
hsdem <- read.csv("hsdem.csv")
hstest <- read.csv("hstest.csv")
hs2 <- merge(hsdem,hstest)

#ex 3
note <- data.frame("Sem 1"=c(8.75,7.35,7.75,9.35,9.75),"Sem 2"=c(9.25,8.35,8.25,9.45,10))
grades <- stack(note)
gradesunstacked <- unstack(grades)

#ex 4
buildings <- data.frame(location=c(1, 2, 3), name=c("building1", "building2", "building3"))
data <- data.frame(survey=c(1,1,1,2,2,2), location=c(1,2,3,2,3,1), efficiency=c(51,64,70,71,80,58))
buildingStats <- merge(buildings,data, by.x = "location")

#ex 5
buildings <- data.frame(location=c(1, 2, 3), name=c("building1", "building2", "building3"))
data <- data.frame(survey=c(1,1,1,2,2,2), LocationID=c(1,2,3,2,3,1),
                   efficiency=c(51,64,70,71,80,58))
buildingStats <- merge(buildings, data, by.x = "location", by.y ="LocationID")

# ex 6
# scoatem argumentul by.x by.y pentru ca este inutile
# merge(buildings, data)

#ex 7
buildingStates <- merge(buildings, data, by.x="location",all=TRUE)

#ex 8
buildingStates <- merge(buildings, data, by="location",all.x=TRUE)

#ex 10
buildings <- data.frame(location=c(1, 2, 3), name=c("building1", "building2", "building3"))
buildings2 <- data.frame(location=c(5, 4, 6), name=c("building5", "building4", "building6"))
buildingStates <- merge(buildings,buildings2, all=TRUE)

# ex 11
world95 <- read.csv("World95.csv")

#