Dear List,
For what I understand, strptime() simply converts from one class
representation to another; i.e., from character to POSIXct/POSIXlt.
One strange feature of this command running on Linux is that there are
repeated calls to system time (as was revealed in a trace of system
calls), which considerably affect performance. These system calls end
up taking almost 75% of the execution time, and are completely
unnecessary.
Code:
ptm <- proc.time()
for (i in 1:100000) strptime("2010-03-10 17:00:00", "%F %H:%M:%S")
(proc.time() -ptm)
Output on Windows Box (32-bit R 2.9.1 running on Intel X5472 @ 3.0 GHz):
user system elapsed
1.31 0.02 1.30
Output on Linux Box (64-bit R 2.10.1 running on Intel Xeon E5520 @
2.27GHz):
user system elapsed
3.33 8.941 12.273
Any help would be appreciated. Also, if I should turn to a different
mailing list for this, please let me know.
Regards,
Alex
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