R CheatSheet
1. Google Map
#reference:https://rpubs.com/Japhilko82/ggmap
FinalMap<-qmap("Australia",zoom=4)
library(RODBC)
dbhandle <- odbcDriverConnect('driver={SQL Server};server=xxx;database=xxx;trusted_connection=true')
data_hrchy <- sqlQuery(dbhandle, 'select * from xxx')
data_company<-unique(data_hrchy[,"Company Name"])
summary(data_company)
library(ggmap)
place<-as.character(data_company)
positions<-geocode(place)
positions
locationt <- geocode("Australia")
mapImageData1 <- get_map(location = locationt,
color = "color",
source = "google",
maptype = "satellite",
zoom = 4)
output_graph<-ggmap(mapImageData1,
extent = "device",
ylab = "Latitude",
xlab = "Longitude")
output_graph + geom_point(data=positions, aes(x=lon, y=lat), color=rgb(1,0.1,0.1), size=5, alpha=0.5)
2.SQL SERVER
library(RODBC)
dbhandle <- odbcDriverConnect('driver={SQL Server};server=SQLAU101MEL0240.GLOBALTEST.ANZ.COM,49168;database=CVA2_FrontEnd;trusted_connection=true')
r <- sqlQuery(dbhandle, 'select * from dbo.BRKR_HRCHY')
3. each row in a set
for (i in 1:nrow(points)) {
print(points[i,])
}
4. data type
typeof
5. remove column
train_data.pick$Fare = NULL
6.check null
summary(train_data$Age)
7. recall memory
gc()
8. add item to vector
v = NULL
for ( i in 1:nrow(train_data.pick)) {
#print(train_data.pick$Sex[i])
if(train_data.pick$Sex[i]=='male'){
v <- c(v,1)
}
else{
v <- c(v,2)
}
}
9. ignore null
na.omit()
10. trim
gdata
11. get letters from string
gsub("pattern","rep",t)
pattern: regular expression
replace substring matching 'pattern' in t with 'rep'
12.char to code
intToUtf8(65)
utf8ToInt("A")
13.