Print out stats about a comp in Nuke. Returns a list of used node classes and their number of occurrences.

comp_stats.py

stats = dict()

for n in nuke.allNodes():
    node_class = str(n.Class())
    if node_class in stats:
        stats[node_class] += 1
    else:
        stats[node_class] = 1

import operator
sorted_stats = sorted(stats.items(), key=operator.itemgetter(1), reverse=True)

for entry in sorted_stats:
    print '{0}: {1}'.format(entry[0], entry[1])