R按来自另一个数据框的列中的值对数据框进行子集，并为每个子集命名

Question

I want to subset a data frame (with millions of data rows) thousands of times, using values in two columns in another data frame. Currently I was using the example provided by Akrun

     subset(df1, (Latitude >= (df2$Lat - 0.01)) & (Latitude <= (df2$Lat + 0.01)))

However, this seems to return all of the data that matches any of the rows in the second data frame. How can I adjust this so that it takes a third column from the second data frame as a name for each row subset pair?

Reference; Subset data frame based on range of values in second data frame

Answer 1

# Subsetted data
df_sub <- subset(df1, (Latitude >= (df2$Lat - 0.01)) & (Latitude <= (df2$Lat + 0.01)))
# Names of third column
towns <- df2$Town[(df1$Latitude >= (df2$Lat - 0.01)) & (df1$Latitude <= (df2$Lat + 0.01))]

df_out <- cbind(df_sub, towns)