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Size: a a a
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dt[, .(v = mean(col)), verbose = TRUE]
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> DT[, .(v = mean(V1)), by = id, verbose = TRUE]
Detected that j uses these columns: V1
Finding groups using forderv ... forder.c received 5000000 rows and 1 columns
0.102s elapsed (0.186s cpu)
Finding group sizes from the positions (can be avoided to save RAM) ... 0.001s elapsed (0.001s cpu)
Getting back original order ... forder.c received a vector type 'integer' length 100000
0.005s elapsed (0.008s cpu)
lapply optimization is on, j unchanged as 'list(mean(V1))'
GForce optimized j to 'list(gmean(V1))'
Making each group and running j (GForce TRUE) ... gforce initial population of grp took 0.062
gforce assign high and low took 0.036
This gsum took (narm=FALSE) ... gather took ... 0.010s
0.021s
gforce eval took 0.021
0.121s elapsed (0.200s cpu)
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dt[, .(v = mean(col)), verbose = TRUE]
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matrixStats
.data.table
посчитать.А
matrixStats
.data.table
посчитать.АК
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C
a
a
C