R Summarize Collapsed Data.Table

问题

I have data such as this

    data=data.table("School"=c(1,1,1,1,1,1,0,1,0,0,1,1,1,0,1,0,1,1,1,1,1,0,0,1,0,1,1,1,1,1,1,0,1,0,1,0),
    "Grade"=c(0,1,1,1,0,0,0,1,1,1,0,1,1,0,0,1,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,0,0,0,1,0),
    "CAT"=c(1,0,1,1,0,1,0,1,1,0,1,0,0,1,0,1,0,0,0,0,0,0,1,0,0,1,1,0,0,1,1,0,1,1,1,1),
    "FOX"=c(1,1,0,1,1,1,1,1,0,0,0,1,1,1,0,0,1,1,1,1,1,1,1,0,1,1,0,0,1,0,0,1,0,0,1,0),
    "DOG"=c(0,0,0,1,0,0,1,0,0,1,0,1,1,1,0,1,1,0,0,1,1,0,0,1,0,1,1,0,1,0,1,1,1,0,1,1))

and wish to achieve a new data table such as this:

dataWANT=data.frame("VARIABLE"=c('CAT', 'CAT', 'CAT', 'FOX', 'FOX', 'FOX', 'DOG', 'DOG', 'DOG'),
"SCHOOL"=c(1, 1, 0, 1, 1, 0, 1, 1, 0),
"GRADE"=c(0, 1, 1, 0, 1, 1, 0, 1, 1),
"MEAN"=c(NA))

dataWANT takes the mean for CAT and FOX and DOG by SCHOOL, GRADE, and SCHOOL X GRADE when they are equal to 1.

I know how to do this one at a time but that is not good for doing this with a big data.

data[, CAT1:=mean(CAT), by=list(SCHOOL)]
data[, FOX1:=mean(FOX), by=list(GRADE)]
data[, DOG1:=mean(DOG), by=list(SCHOOL, GRADE)]

data$CAT2 = unique(data[SCHOOL==1, CAT1])
data$FOX2 = unique(data[GRADE==1, FOX1])
data$DOG2 = unique(data[SCHOOL==1 & GRADE==1, DOG1])

Please only use this:

data=data.table("SCHOOL"=c(1,1,1,1,1,1,0,1,0,0,1,1,1,0,1,0,1,1,1,1,1,0,0,1,0,1,1,1,1,1,1,0,1,0,1,0),
                "GRADE"=c(0,1,1,1,0,0,0,1,1,1,0,1,1,0,0,1,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,0,0,0,1,0),
                "CAT"=c(1,0,1,1,0,1,0,1,1,0,1,0,0,1,0,1,0,0,0,0,0,0,1,0,0,1,1,0,0,1,1,0,1,1,1,1),
                "FOX"=c(1,0,0,1,1,1,1,1,0,0,0,1,1,1,0,0,1,1,1,1,1,1,1,0,1,1,0,0,1,0,0,1,0,0,1,0),
                "DOG"=c(0,0,0,1,0,0,1,0,0,1,0,1,1,1,0,1,1,0,0,1,1,0,0,1,0,1,1,0,1,0,1,1,1,0,1,1))


data[, CAT1:=mean(CAT), by=list(SCHOOL)]
data[, CAT2:=mean(CAT), by=list(GRADE)]
data[, CAT3:=mean(CAT), by=list(SCHOOL, GRADE)]

data[, FOX1:=mean(FOX), by=list(SCHOOL)]
data[, FOX2:=mean(FOX), by=list(GRADE)]
data[, FOX3:=mean(FOX), by=list(SCHOOL, GRADE)]

data[, DOG1:=mean(DOG), by=list(SCHOOL)]
data[, DOG2:=mean(DOG), by=list(GRADE)]
data[, DOG3:=mean(DOG), by=list(SCHOOL, GRADE)]

dataWANT=data.frame("VARIABLE"=c('CAT','CAT','CAT','FOX','FOX','FOX','DOG','DOG','DOG'),
                    "TYPE"=c(1,2,3,1,2,3,1,2,3),
                    "MEAN"=c(0.48,0.44,0.428,0.6,0.611,0.6428,0.52,0.61,0.6428))

where TYPE equals to 1 when MEAN in estimated by SCHOOL,

TYPE equals to 2 when MEAN is estimated by GRADE,

TYPE equals to 3 when MEAN is estimated by SCHOOL and GRADE

回答1:

We could use rbindlist after creating a list by taking the MEAN after melting the dataset (as in the other post)

library(data.table)
cols <- c('CAT', 'FOX', 'DOG')
data1 <- melt(data, measure.vars = cols)
list_cols <- list('SCHOOL', 'GRADE', c('SCHOOL', 'GRADE'))
lst1 <- lapply(list_cols, function(x)  
       data1[, .(MEAN = mean(value, na.rm = TRUE)), c(x, 'variable')])
rbindlist(lapply(lst1, function(x)  {
     nm1 <- setdiff(names(x), c('variable', 'MEAN'))
     x[Reduce(`&`, lapply(mget(nm1), as.logical)),
     .(VARIABLE = variable, MEAN)]}), idcol = 'TYPE')[order(VARIABLE)]
#   TYPE VARIABLE      MEAN
#1:    1      CAT 0.4800000
#2:    2      CAT 0.4444444
#3:    3      CAT 0.4285714
#4:    1      FOX 0.6000000
#5:    2      FOX 0.5555556
#6:    3      FOX 0.6428571
#7:    1      DOG 0.5200000
#8:    2      DOG 0.6111111
#9:    3      DOG 0.6428571

回答2:

Do you mean to get something like this?

library(data.table)

melt(data, measure.vars = c('CAT', 'FOX', 'DOG'))[, 
        .(MEAN = mean(value, na.rm = TRUE)), .(School, Grade, variable)]

To group it by different columns, we can do :

cols <- c('CAT', 'FOX', 'DOG')
data1 <- melt(data, measure.vars = cols)
list_cols <- list('School', 'Grade', c('School', 'Grade'))

lapply(list_cols, function(x)  
         data1[, .(MEAN = mean(value, na.rm = TRUE)), c(x, 'variable')])

回答3:

You could subset and calculate your means first using lapply(.SD,...) then melt that into your output:

melt(data[School != 0 | Grade != 0, lapply(.SD, mean), by = .(School, Grade)], id.vars = c("School", "Grade"))

Adding this after also adds the TYPE variable

...][, TYPE := School + (2*Grade)]

Putting it all together and tidying it up too, it matches your desired output

dataWANT <- melt(data[School != 0 | Grade != 0, lapply(.SD, mean), by = .(School, Grade)], id.vars = c("School", "Grade"))[, TYPE := School + (2*Grade)][order(variable, TYPE), .("VARIABLE" = variable, TYPE, "MEAN" = value)]

来源：https://stackoverflow.com/questions/61611000/r-summarize-collapsed-data-table

标签

data.table

summary