merge rows with same values

Question

I'm new to R and I would like to merge those two data frame, because the rows have the same X and Y values :

#df1
OBJECTID urban_sprawl_copy       X       Y              agriculture_sprawl forest_sprawl
158448                 0         1235546 1100801                  0             0
158510                 0         1235546 1100513                  0             0
158447                 0         1235258 1100801                  0             0
158509                 0         1235258 1100513                  0             0
158571                 0         1235258 1100225                  0             0
62247                  0         1234970 1088991                  0             0

#df2
 X       Y       dist_to_urban_2015
1235546 1100801  40963.63
1235546 1100513  40753.46
1235258 1100801  40767.71
1235258 1100513  40556.52
1235258 1100225  40346.29
1234970 1100801  40572.89

I do so with this :

merged <- merge(df1, df2, all=TRUE)

But I end up with something like this :

#merged
X       Y         OBJECTID urban_sprawl_copy agriculture_sprawl forest_sprawl dist_to_urban_2015                
1235546 1100513   158510                 0                  0             0  NA         
1235546 1100801   158448                 0                  0             0         
1235546 1100513       NA                NA                 NA            NA  40753.46           
1235546 1100801       NA                NA                 NA            NA  40753.46  
1235258 1100225   158571                 0                  0             0  NA
1235258 1100513   158509                 0                  0             0  NA

I would like to merge the rows with same X and Y values, like seen in this thread.

So using something like this

Myfunc <- function(x) x[x != '']
df %>%
  group_by(X,Y) %>%
  summarise_each(funs(Myfunc))

But it does'nt seem to work. Does anyone have an idea why ?

This is a simplified version because I have like 25 variables and I'm new to stackoverflow, so excuse me in advance if it doesn't fit with the rules of publication.

Thanks!