将键（都出现在给定的字符串中）映射到字符串中的位置

Question

我尝试获取字符串中键的所有索引并将它们存储在dict中，以便 每个索引都有一个映射到它的键列表。你知道吗

示例：

string = "loloo and foofoo at the foo bar"
keys = "foo", "loo", "bar", "lo"

我想是这样的

{ 
  0: [lo]
  2: [loo, lo]
 10: [foo]
 13: [foo]
 24: [foo]
 28: [bar]
}

我目前的答案如下：

def get_index_for_string(string, keys):
    """
    Get all indexes of the keys in the string and store them in a dict, so that
    every index has a list of keys mapping to it.
    """
    key_in_string = dict((key, [m.start() for m in re.finditer(key, string)])
                            for key in keys if key in string)
    index_of_keys = {}
    for key, values in key_in_string.items():
        for value in values:
            if not value in index_of_keys:
                index_of_keys[value] = []
            index_of_keys[value].append(key)
    return index_of_keys

有什么好的建议吗？你知道吗

Answer 1

你在寻找什么样的“更好”？如果需要更好的Big-O复杂性，可以使用Aho-Corasic Automaton。Python提供了一些快速实现：

• https://github.com/scoder/acora
• http://pypi.python.org/pypi/ahocorasick