## ----readCSV-------------------------------------------------------------
read.csv


## ----readCSV2, comment="",results='markup'-------------------------------
mon = read.csv("data/Monuments.csv",header=TRUE,as.is=TRUE)
head(mon)


## ----subset5, comment="", prompt=TRUE------------------------------------
colnames(mon)
head(mon$zipCode)
head(mon$neighborhood)


## ----workingDirectory, comment="", prompt=TRUE---------------------------
## get the working directory
getwd()
setwd("~/Dropbox/winterR_2015/Lectures")


## ----directoryNav, comment="", prompt=TRUE-------------------------------
dir("./") # shows directory contents
dir("..")


## ----readCSV3, comment="", prompt=TRUE-----------------------------------
class(mon)
str(mon)


## ----names1, comment="", prompt=TRUE-------------------------------------
names(mon)[1] = "Name"
names(mon)
names(mon)[1] = "name"
names(mon)


## ----logical1, comment="", prompt=TRUE-----------------------------------
z = c(TRUE,FALSE,TRUE,FALSE)
class(z)
sum(z) # number of TRUEs


## ----logical2, comment="", prompt=TRUE-----------------------------------
z2 = c("TRUE","FALSE","TRUE","FALSE")
class(z2)
sum(z2)
identical(z,z2)


## ----logical3, comment="", prompt=TRUE-----------------------------------
x = 1:6
x > 4
x == 3


## ----logical4, comment="", prompt=TRUE-----------------------------------
Index = (mon$zipCode == 21202)
sum(Index)
table(Index)
mon2 = mon[Index,] 


## ----logical5, comment="", prompt=TRUE-----------------------------------
dim(mon2)
head(mon2)


## ----which, comment="", prompt=TRUE--------------------------------------
mon$Location.1 != ""
which(mon$Location.1 != "")


## ----q1, comment="", prompt=TRUE-----------------------------------------
names(mon)
names(mon)[6] = "location"
names(mon)


## ----q2, comment="", prompt=TRUE-----------------------------------------
nrow(mon)
dim(mon)
length(mon$name)


## ----q3a, comment="", prompt=TRUE----------------------------------------
unique(mon$zipCode)
unique(mon$policeDistrict)
unique(mon$councilDistrict)


## ----q3b, comment="", prompt=TRUE----------------------------------------
unique(mon$neighborhood)


## ----q3c, comment="", prompt=TRUE----------------------------------------
length(unique(mon$zipCode))
length(unique(mon$policeDistrict))
length(unique(mon$councilDistrict))
length(unique(mon$neighborhood))


## ----q3d, comment="", prompt=TRUE----------------------------------------
table(mon$zipCode)
length(table(mon$zipCode))


## ----q4a, comment="", prompt=TRUE----------------------------------------
tab = table(mon$zipCode, mon$neighborhood)
# tab
tab[,"Downtown"]
length(unique(tab[,"Downtown"]))


## ----q4b, comment="", prompt=TRUE----------------------------------------
tt = tab[,"Downtown"]
tt
tt == 0 # which entries are equal to 0


## ----q4c, comment="", prompt=TRUE----------------------------------------
tab[,"Downtown"] !=0
sum(tab[,"Downtown"] !=0)
sum(tab[,"Johns Hopkins Homewood"] !=0)


## ----q4d, comment="", prompt=TRUE----------------------------------------
dt = mon[mon$neighborhood == "Downtown",]
head(mon$neighborhood == "Downtown",10)
dim(dt)
length(unique(dt$zipCode))


## ----q5, comment="", prompt=TRUE-----------------------------------------
head(mon$location)
table(mon$location != "") # FALSE=DO NOT and TRUE=DO


## ----q6a, comment="", prompt=TRUE----------------------------------------
tabZ = table(mon$zipCode)
head(tabZ)
max(tabZ)
tabZ[tabZ == max(tabZ)]


## ----q6b, comment="", prompt=TRUE----------------------------------------
which.max(tabZ) # this is the element number
tabZ[which.max(tabZ)] # this is the actual maximum


## ----q6c, comment="", prompt=TRUE----------------------------------------
tabN = table(mon$neighborhood)
tabN[which.max(tabN)] 
tabC = table(mon$councilDistrict)
tabC[which.max(tabC)] 
tabP = table(mon$policeDistrict)
tabP[which.max(tabP)] 


## ----q7, comment="", prompt=TRUE-----------------------------------------
monTab = read.delim("http://biostat.jhsph.edu/~ajaffe/winterR_2015/data/Monuments-tab.txt",
                    header=TRUE, as.is=TRUE)
identical(mon$name,monTab$name)