[英]convert list of strings to unique lowercase, preserving order (python 2.7)
我想将字符串列表转换为小写并在保留顺序的同时删除重复项。 我在StackOverflow上发现的许多单行Python魔术将字符串列表转换为小写字母,但似乎顺序丢失了。
我已经编写了下面的代码,该代码可以正常工作,并且很高兴坚持使用。 但是我想知道是否有一种方法可以实现更多的Python语言和更少的代码(如果将来我要写类似的东西,那么可能会减少错误的发生。这花了我相当长的时间来写)。
def word_list_to_lower(words):
""" takes a word list with a special order (e.g. frequency)
returns a new word list all in lower case with no uniques but preserving order"""
print("word_list_to_lower")
# save orders in a dict
orders = dict()
for i in range(len(words)):
wl = words[i].lower()
# save index of first occurence of the word (prioritizing top value)
if wl not in orders:
orders[wl] = i
# contains unique lower case words, but in wrong order
words_unique = list(set(map(str.lower, words)))
# reconstruct sparse list in correct order
words_lower = [''] * len(words)
for w in words_unique:
i = orders[w]
words_lower[i] = w
# remove blank entries
words_lower = [s for s in words_lower if s!='']
return words_lower
略微修改“ 如何在保留顺序的同时从列表中删除重复项”中的答案?
def f7(seq):
seen = set()
seen_add = seen.add
seq = (x.lower() for x in seq)
return [x for x in seq if not (x in seen or seen_add(x))]
您也可以:
pip install orderedset
接着:
from orderedset import OrderedSet
initial_list = ['ONE','one','TWO','two','THREE','three']
unique_list = [x.lower() for x in list(OrderedSet(initial_list))]
print unique_list
只需执行以下操作:
initial_list = ['ONE','one','TWO','two']
uninique_list = [x.lower() for x in list(set(initial_list))]
print unique_list
initial_list = ['ONE','one','TWO','two']
new_list = []
[new_list.append(s.lower()) for s in initial_list if s.lower() not in new_list]
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