Combine two data frames and remove duplicate columns

问题

I want to cbind two data frames and remove duplicated columns. For example:

df1 <- data.frame(var1=c('a','b','c'), var2=c(1,2,3))
df2 <- data.frame(var1=c('a','b','c'), var3=c(2,4,6))

cbind(df1,df2) #this creates a data frame in which column var1 is duplicated

I want to create a data frame with columns var1, var2 and var3, in which column var2 is not repeated.

回答1:

merge will do that work.

try:

merge(df1, df2)

回答2:

In case you inherit someone else's dataset and end up with duplicate columns somehow and want to deal with them, this is a nice way to do it:

for (name in unique(names(testframe))) {
  if (length(which(names(testframe)==name)) > 1) {
    ## Deal with duplicates here. In this example
    ## just print name and column #s of duplicates:
    print(name)
    print(which(names(testframe)==name))
  }
}

来源：https://stackoverflow.com/questions/7440917/combine-two-data-frames-and-remove-duplicate-columns