Python 从列表中返回唯一单词（不区分大小写）

Question

我需要帮助才能按顺序从列表中返回唯一字词（不区分大小写）。

例如：

def case_insensitive_unique_list(["We", "are", "one", "we", "are", "the", "world", "we", "are", "THE", "UNIVERSE"])

将返回： [“我们”、“是”、“一个”、“这个”、“世界”、“宇宙”]

到目前为止，这是我所拥有的：

def case_insensitive_unique_list(list_string):

uppercase = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
lowercase = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]

temp_unique_list = []

for i in list_string:
    if i not in list_string:
        temp_unique_list.append(i)

我无法比较 temp_unique_list 中的每个单词，无论该单词是否重复。例如：“to”和“To”（我假设 range 函数会很有用）

并使其返回该函数将接收的原始列表中第一个出现的单词。

我将如何使用 for 循环来做到这一点？

Answer 1

您可以借助 for 循环和 set 数据结构来做到这一点，就像这样

def case_insensitive_unique_list(data):
    seen, result = set(), []
    for item in data:
        if item.lower() not in seen:
            seen.add(item.lower())
            result.append(item)
    return result

输出

['We', 'are', 'one', 'the', 'world', 'UNIVERSE']

Answer 2

您可以使用set() 和列表理解：

>>> seen = set()
>>> lst = ["We", "are", "one", "we", "are", "the", "world", "we", "are", "THE", "UNIVERSE"]
>>> [x for x in lst if x.lower() not in seen and not seen.add(x.lower())]
['We', 'are', 'one', 'the', 'world', 'UNIVERSE']

Answer 3

你可以这样做：

l = ["We", "are", "one", "we", "are", "the", "world", "we", "are", "THE", "UNIVERSE"]

a = []

for i in l:
    if i.lower() not in [j.lower() for j in a]:
        a.append(i)

>>> print a
['We', 'are', 'one', 'the', 'world', 'UNIVERSE']

Answer 4

l=["We", "are", "one", "we", "are", "the", "world", "we", "are", "THE", "UNIVERSE"]
so=[]
for w in l:
    if w.lower() not in so:
        so.append(w.lower())

In [14]: so
Out[14]: ['we', 'are', 'one', 'the', 'world', 'universe']

Answer 5

您可以使用集合来确保唯一性。当您尝试将重复项添加到集合中时，如果它已经存在，它将简单地丢弃它。

您还应该使用内置的 lower() 函数来管理不区分大小写。

uniques = set()
for word in words:
    set.add(word.lower()) #lower it first and then add it

如果这是用于家庭作业并且使用 set 是禁止的，那么您可以轻松地将其调整为仅使用列表，只需循环并添加条件：

uniques = list()
if word.lower() not in uniques:
    #etc

Answer 6

你可以像这样使用collections.OrderedDict。

from collections import OrderedDict
def case_insensitive_unique_list(data):
    d = OrderedDict()
    for word in data:
        d.setdefault(word.lower(), word)
    return d.values()

输出：

['We', 'are', 'one', 'the', 'world', 'UNIVERSE']

Answer 7

好的，删除了我之前的答案，因为我误读了 OP 的帖子。我所有的歉意。

作为一个借口，为了它的乐趣和以不同的方式做它，这里有另一种解决方案，虽然它既不是最有效的，也不是最好的：

>>> from functools import reduce
>>> for it in reduce(lambda l,it: l if it in set({i.lower() for i in l}) else l+[it], lst, []):
...     print(it, end=", ")