CODEWITHSUNDEEP
rdataframe
Giuseppe Petri
Giuseppe Petri

Reputation: 640

How to assign specific values to a factorial dataframe?

I am calculating a summary (mean) from a set of locations. And then need to re-assign these mean values to the locations from where these means were calculated.

What I did was to calculate those means and tried to create a new variable (average.yield) that assign the mean yield of the locations to each individual location. 

cultivar <- c("cultivar_A", "cultivar_B")
data1 <- expand.grid(locs, cultivar)
yield <- c(7000, 5000, 2000, 7000, 6000, 5000) 
data1$yield <-  yield
colnames(data1) <- c("locs", "cultivar", "yield")


mean.yield.loc <- data1 %>%
                    group_by(locs) %>%
                    summarise(mean.yield = mean(yield))

data1 %>% 
        group_by(locs, cultivar) %>%
        mutate(average.yield = mean.yield.loc$mean.yield)

I expected something like this.. 

locs   cultivar yield   average.yield
Loc_1 cultivar_A  7000  7000
Loc_2 cultivar_A  5000  5500
Loc_3 cultivar_A  2000  3500
Loc_1 cultivar_B  7000  7000
Loc_2 cultivar_B  6000  5500
Loc_3 cultivar_B  5000  3500

And this is the error: Error: Column `average.yield` must be length 1 (the group size), not 3

Upvotes: 0

Views: 47

Answers (1)

Jason Mathews
Jason Mathews

Reputation: 805

Just use the merge function.

merge(data1,mean.yield.loc, by.x = "locs", by.y = "locs")

  locs   cultivar yield mean.yield
1 Loc_1 cultivar_A  7000       7000
2 Loc_1 cultivar_B  7000       7000
3 Loc_2 cultivar_A  5000       5500
4 Loc_2 cultivar_B  6000       5500
5 Loc_3 cultivar_A  2000       3500
6 Loc_3 cultivar_B  5000       3500

Upvotes: 1

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