#!/usr/bin/python3 import argparse, json, random, sys parser = argparse.ArgumentParser() parser.add_argument('--infile', type=argparse.FileType('r'), default=sys.stdin) parser.add_argument('--outfile', type=argparse.FileType('w'), default=sys.stdout) args = parser.parse_args() data = json.load(args.infile) print(len(data['values'])) print(int(len(data['values']) / 1000)) sample = random.sample(data['values'], int(len(data['values']) / 1000)) print(len(sample)) # Sort by timestamp (the second element) # take second element for sort def takeSecond(elem): return elem[1] sample.sort(key=takeSecond) data['values'] = sample json.dump(data, args.outfile)