For all *.txt and *.awd files in the data folder, calculate the sum of each line across all files starting at the 20th value.

process.py

import glob

output = []

# For both extensions
for ext in ["txt", "awd"]:
	# For all files matching the current extension
	for filename in glob.iglob("data/*.{}".format(ext)):
		print filename
		
		# For each line in current file
		for idx, line in enumerate(open(filename)):
			# Skip first 19 lines
			if idx < 19:
				continue

			# Array offset (arrays are 0-indexed)
			offset = idx - 19

			# If the output array isn't long enough, append an element
			if len(output) <= offset:
				output.append(0)

			# Add current value to the output array at the current offset
			output[offset] += int(line)

# Create the output file
with open("sums.txt", "w") as sums:
	# Write all sums, one per line
	for val in output:
		print >>sums, val