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@MichaelChirico
Created November 14, 2023 00:49
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grep() slower than which(grepl())??
library(microbenchmark)
N = 1e4
v = sample(letters, N, TRUE)
microbenchmark(times = 200L, grep("a", v), which(grepl("a", v)), grep("[a-m]", v), which(grepl("[a-m]", v)), grep("[a-z]", v), which(grepl("[a-z]", v)))
# Unit: microseconds
# expr min lq mean median uq max neval cld
# grep("a", v) 630.561 640.4110 670.5257 655.4915 680.6115 866.132 200 b
# which(grepl("a", v)) 598.802 609.5220 637.0542 621.0965 652.9120 839.231 200 a
# grep("[a-m]", v) 692.601 708.4215 735.6788 721.3065 744.6365 1207.722 200 d
# which(grepl("[a-m]", v)) 652.362 671.8470 704.9352 687.3010 719.2070 1007.502 200 c
# grep("[a-z]", v) 639.452 649.2360 683.5104 661.7870 688.1360 1161.722 200 b
# which(grepl("[a-z]", v)) 589.322 598.3860 629.4264 607.7310 639.5370 1113.842 200 a
Ditto for N=1e7
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