12.1 Program 'randomselect.py'

This simple program reads in a data file and randomly selects records according to the given argument. It writes these records unchanged into the output file. The program assumes that each record corresponds to one line.

The program is called from the command line with either the argument list

python randomselect.py in_file out_file -perc percentage_value

python randomselect.py in_file out_file -num num_records

The needed arguments are

in_file
Name of the input file with the original data records.
out_file
Name of the output file where the randomly selected records are written into.
-perc percentage_value
Set the percentage of how many records should be selected randomly. The percentage value must be larger than 0.0 and smaller than 100.0.
-num num_records
Alternatively, the absolute number of records to be selected randomly can be given as an argument. The value must be positive, and smaller than the total number of records in the input file.