mapping characters across data frames in R [duplicate]

Question

I have a large dataframe where I have two versions of an id variable (name1 and name2). I want to somehow link these ids so that in a new (much larger) data frame when I encounter name1 I can create a new column that populates with name2.

Here is an example. In df1 we have name1 and name2.

df1 <- data.frame(name1 = c('AAA', 'AAB', 'AAC'), name2 = c('top', 'mid', 'bottom'))

Now I want to make a new larger data frame, df2 where I have only name1, and create a new column that uses the mapping from df1 to add a new column to df2, name2 which populates using 'AAA' == 'top'; 'AAB' == 'mid'; 'AAC' == 'bottom'.

df2 <- data.frame(name1 = c(rep('AAA', 10), rep('AAB', 10), rep('AAC', 10)))

This is obviously a minimal example, the data I am dealing with contains 500k rows and 850 unique ids for name1 and name2 so Im looking for something relatively quick.