A filter to normalise focal lengths to the nearest standard focal length

standardise_fl.py

#!/usr/bin/python
import sys
limits = [16.0, 24.0, 28.0, 35.0, 50.0, 70.0, 85.0, 105.0, 135.0, 150.0, 180.0, 200.0, 210.0, 300.0, 450.0, 600.0]
if __name__ == "__main__":

    for line in sys.stdin:
        fl = float(line)
        diffs = dict([(abs(x - fl), x) for x in limits])
        print diffs[min(diffs)]