old_contents: import re
  
  errorFile = open('samples/foobar2000-errors.txt', 'r')
  errors = errorFile.readlines()
  
  index = -1
  for i in range(len(errors)):
  	line = errors[i]
  	if re.search(r'List of undecodable items:', line):
  		index = i
  
  nbErrorsFoobar = 0
  for i in range(index, len(errors)):
  	line = errors[i]
  	match = re.search(r'"(.*.flac)"', line)
  	if match:
  		nbErrorsFoobar += 1
  		print(match.group(1))
  
  errorFile.close()
  
  errorFile = open('samples/dbpoweramp-errors.txt', 'r')
  errors = errorFile.readlines()
  
  index = -1
  nbErrorsDbPowerAmp = 0
  for i in range(len(errors)):
  	line = errors[i]
  	match = re.search(r'/.+/[^/]+.flac', line)
  	if match:
  		print(match.group())
  	if (re.search(r'Encountered', line) or re.search(r'md5 did not match decoded data, file is corrupt.', line)):
  		nbErrorsDbPowerAmp += 1
  
  print(nbErrorsFoobar, 'FLAC errors from foobar2000')
  print(nbErrorsDbPowerAmp, 'FLAC errors from dbPowerAmp')
new_contents: import re
  
  errorFile = open('samples/foobar2000-errors.txt', 'r')
  errors = errorFile.readlines()
  errorsSet = set()
  
  index = -1
  for i in range(len(errors)):
  	line = errors[i]
  	if re.search(r'List of undecodable items:', line):
  		index = i
  
  nbErrorsFoobar = 0
  for i in range(index, len(errors)):
  	line = errors[i]
  	match = re.search(r'\\.+\\([^\\]+.flac)', line)
  	if match:
  		errorsSet.add(match.group(1))
  		nbErrorsFoobar += 1
  		# print(match.group(1))
  
  errorFile.close()
  
  errorFile = open('samples/dbpoweramp-errors.txt', 'r')
  errors = errorFile.readlines()
  
  index = -1
  nbErrorsDbPowerAmp = 0
  for i in range(len(errors)):
  	line = errors[i]
  	match = re.search(r'/.+/([^/]+.flac)', line)
  	if match:
  		errorsSet.add(match.group(1))
  		# print(match.group(1))
  	if (re.search(r'Encountered', line) or re.search(r'md5 did not match decoded data, file is corrupt.', line)):
  		nbErrorsDbPowerAmp += 1
  
  print(nbErrorsFoobar, 'FLAC errors from foobar2000')
  print(nbErrorsDbPowerAmp, 'FLAC errors from dbPowerAmp')
  print(len(errorsSet))
  
  for item in errorsSet:
  	print(item)
subject: Use a Set to avoid duplicates