我有一个字符串和一个字典，我必须替换该文本中每次出现的dict键。
text = 'I have a smartphone and a Smart TV'
dict = {
'smartphone': 'toy',
'smart tv': 'junk'
}
如果键中没有空格，我将把文本分解成单词，然后与dict逐一比较。看起来花了O（n）。但是现在钥匙里面有空间，所以事情变得更加复杂。请建议我这样做的好方法，并请注意密钥可能与文本的大小写不匹配。
更新
我已经想到了这种解决方案，但是效率不高。O（m * n）或更多...
for k,v in dict.iteritems():
text = text.replace(k,v) #or regex...
如果文字中的关键字彼此之间不太接近（关键字其他关键字），我们可以这样做。把O（n）交给我>“ <
def dict_replace(dictionary, text, strip_chars=None, replace_func=None):
"""
Replace word or word phrase in text with keyword in dictionary.
Arguments:
dictionary: dict with key:value, key should be in lower case
text: string to replace
strip_chars: string contain character to be strip out of each word
replace_func: function if exist will transform final replacement.
Must have 2 params as key and value
Return:
string
Example:
my_dict = {
"hello": "hallo",
"hallo": "hello", # Only one pass, don't worry
"smart tv": "http://google.com?q=smart+tv"
}
dict_replace(my_dict, "hello google smart tv",
replace_func=lambda k,v: '[%s](%s)'%(k,v))
"""
# First break word phrase in dictionary into single word
dictionary = dictionary.copy()
for key in dictionary.keys():
if ' ' in key:
key_parts = key.split()
for part in key_parts:
# Mark single word with False
if part not in dictionary:
dictionary[part] = False
# Break text into words and compare one by one
result = []
words = text.split()
words.append('')
last_match = '' # Last keyword (lower) match
original = '' # Last match in original
for word in words:
key_word = word.lower().strip(strip_chars) if \
strip_chars is not None else word.lower()
if key_word in dictionary:
last_match = last_match + ' ' + key_word if \
last_match != '' else key_word
original = original + ' ' + word if \
original != '' else word
else:
if last_match != '':
# If match whole word
if last_match in dictionary and dictionary[last_match] != False:
if replace_func is not None:
result.append(replace_func(original, dictionary[last_match]))
else:
result.append(dictionary[last_match])
else:
# Only match partial of keyword
match_parts = last_match.split(' ')
match_original = original.split(' ')
for i in xrange(0, len(match_parts)):
if match_parts[i] in dictionary and \
dictionary[match_parts[i]] != False:
if replace_func is not None:
result.append(replace_func(match_original[i], dictionary[match_parts[i]]))
else:
result.append(dictionary[match_parts[i]])
result.append(word)
last_match = ''
original = ''
return ' '.join(result)
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