mapper.py

def words_map(filepaths, start_pos, end_post, word_pos, delim=' '):
	mapper = {}

	for filepath in filepaths:
		with open(filepath, 'r') as f:
			for row in f:
				row = row.split(delim)
				if row[word_pos] not in mapper.keys():
					mapper[row[word_pos]] = {}
				if filepath not in mapper[row[word_pos]].keys():
					mapper[row[word_pos]][filepath] = []

				mapper[row[word_pos]][filepath].append({
					'start': row[start_pos],
					'end': row[end_post]
					})
	return mapper

print(words_map(['file1.txt', 'file2.txt'], 0, 1, -1))

INPUT:
file1.txt
0.0 1.0 THIS
1.1 1.3 IS
1.4 1.6 AMERICA

file2.txt
0.0 0.6 COLUMBUS
0.7 1.5 DISCOVERED
1.6 2.0 AMERICA

OUTPUT:
  {
    'THIS\n': {
      'file1.txt': [{'start': '0.0', 'end': '1.0'}]
    }, 
    'IS\n': {
      'file1.txt': [{'start': '1.1', 'end': '1.3'}]
    }, 
    'AMERICA\n': {
      'file1.txt': [{'start': '1.4', 'end': '1.6'}], 
      'file2.txt': [{'start': '1.6', 'end': '2.0'}]
    }, 
    'COLUMBUS\n': {
      'file2.txt': [{'start': '0.0', 'end': '0.6'}]
    }, 
    'DISCOVERED\n': {
      'file2.txt': [{'start': '0.7', 'end': '1.5'}]
    }
  }