casting - Recast in R with sum+product -

i have data frame looks this:

x   y   value   weight 10  1   red 1 3.4 5   blue    2 10  10  blue    0.5 3   8   blue    0.5 3   8   red 4 10  1   blue    1 3   8   blue    2 3   8   blue    0.25 

i want recast each row unique combination of "x" , "y", , columns sums of "weight"s each different value of "value". if possible, i'd also have columns raw counts of values of "value". these data be:

x   y   red_count   blue_count  red_sum_of_weights  blue_sum_of_weights 10  1   1   1   1   1 3.4 5   0   1   0   2 10  10  0   0   1   0.5 3   8   1   3   4   2.75 

is there way reshape or reshape2? can counts of values with

dcast(data,x+y~value) 

but haven't been able figure out how use weights in way want to. need work arbitrary number of possible levels value , arbitrary different number of rows per x*y combination in original dataset. i've written own code using loops this, takes extremely long time run - far has taken 6 hours first 15% of 600k row dataset, isn't practical! i'm sure there must way existing functions?

thanks in advance help!

you can combination of dplyr , reshape2 functions. first, group x, y , value (we change name of latter color avoid duplicate column names after melting) , calculate count , sum each sub-group. meltthe result put newly calculated summaries in "long" format. finally, dcast "wide" format asked for.

library(reshape2) library(dplyr)  df %>% group_by(x,y,color=value) %>%    summarise(count=n(), sum=sum(weight)) %>%   melt(id.var=c("x","y","color")) %>%   dcast(x + y ~ variable + color) 

     x  y count_blue count_red sum_blue sum_red 1  3.0  8          3         1     2.75       4 2  3.4  5          1        na     2.00      na 3 10.0  1          1         1     1.00       1 4 10.0 10          1        na     0.50      na