R Skill: Manipulate R data.frame

R-data.frame

Feb 23, 2017

Count number of records in data.frame:

resultDf <- data.frame(table(df$colName))

Intersection of two data.frame:

resultDf <- merge(x=df1, y=df2, by=c("common_column_name"))

Union of two data.frame:

resultDf <- merge(x=df1, y=df2, by=c("common_column_name"), all=TRUE)

Exclusion of two data.frame: (record values in dfa but not in dfb)

resultDf <- dfa[!(dfa$colValue %in% dfb$colValue),]

Compute values by levels:

resultDf <- aggregate(df$colValue, list(df$colName), max)

resultDf <- aggregate(df$colValue, list(df$colName), mean)