R_code_snippets

r_code_snippets

# Read csv file
dfName = read.csv("file.csv")


# READ CSV FILE WITH DATATYPE DEFINED FOR A CERTAIN COLUMN s
dfName <- read.csv("file.csv",colClasses=c("date"="Date"))

# WRITE CSV FILE
write.csv(dfName, file="file.csv")

# CREATE FRAME
dfName <- data.frame(ids, dimensions)

# CREATE FRAME WITH DATE
dfName <- data.frame(ids,as.Date(dates))

# VIEW DATA
head(dfName)
view(dfName)

# ADD COLUMN TO FRAME
dfNameNew <- within(dfName, {newField = "dummy"})

# ADD COLUMN TO FRAME with IF statement
dfNameNew <- within(dfName, {newField = ifelse(actual <= target,1,0)})

# RENAME A COLUMN
rename(dfName,c("old"="new"))

# REMOVE FRAME
remove(dfName)

# GET CLASS OF VARIABLE
class(varName)

# GET CLASS OF ALL COLUMNS IN DATA FRAME
sapply(dfName, class)

# FORMAT A DATE AS YEAR-WEEK
week = format(dfName$date,format="%Y-%U")

# GROUP BY AND SUMMARIZE VALUE
ddply(dfName,.(dimension), summarize, count=sum(intVar))

# GROUP BY AND SUMMARIZE MULTIPLE VALUES
ddply(ops6,.(dimension,week),summarize,count=sum(met),missed=sum(actual>target))

# SORT COLUMN
dfName <- dfName[order(dfName$columnName),]