A simple implementation of reservoire sampling in go. Reservoire sampling can be used to uniformly sample a fixed number of elements from a set of unknown size.
Given a file test.txt with
header
line 1
line 2
line 3
line 4
line 5
the binary can be used as a line filter or with file names as parameters
> cat test.txt | rsample -n=3 -header -seed=0
header
line 1
line 2
line 4
> rsample -n=4 -header -outfile=out.txt -seed=1 test.txt
> cat out.txt
header
line 1
line 5
line 3
line 4
> rsample -help
Usage of rsample:
-header
if true, the first line of the input is preserved and does not count towards n. In case of multiple input files, only the first header is preserved, all other headers are skipped.
-n int
number of samples to be drawn (default 1)
-outfile string
output file. Leave empty to write to stdout.
-seed int
random seed. If not specified, time.Now() is used.