def insenStringCompare(s1, s2):
    """ Method that takes two strings and returns True or False, based
        on if they are equal, regardless of case."""
    try:
        return s1.lower() == s2.lower()
    except AttributeError:
        print "Please only pass strings into this method."
        print "You passed a %s and %s" % (s1.__class__, s2.__class__)

假设ASCII字符串:

string1 = 'Hello'
string2 = 'hello'

if string1.lower() == string2.lower():
    print("The strings are the same (case insensitive)")
else:
    print("The strings are NOT the same (case insensitive)")

从Python 3.3开始，casefold()是一个更好的选择:

string1 = 'Hello'
string2 = 'hello'

if string1.casefold() == string2.casefold():
    print("The strings are the same (case insensitive)")
else:
    print("The strings are NOT the same (case insensitive)")

如果您想要一个处理更复杂unicode比较的更全面的解决方案，请参阅其他答案。

您可以使用casefold()方法。casefold()方法在比较时忽略案例。

firstString = "Hi EVERYONE"
secondString = "Hi everyone"

if firstString.casefold() == secondString.casefold():
    print('The strings are equal.')
else:
    print('The strings are not equal.')

输出:

The strings are equal.

通常的方法是将字符串大写或小写，以便进行查找和比较。例如:

>>> "hello".upper() == "HELLO".upper()
True
>>> 

以不区分大小写的方式比较字符串似乎无关紧要，但事实并非如此。我将使用Python 3，因为Python 2在这里还不发达。

首先要注意的是，Unicode中的大小写删除转换并不简单。存在text.lower() != text.upper().lower()的文本，例如"ß":

>>> "ß".lower()
'ß'
>>> "ß".upper().lower()
'ss'

但是让我们假设你想无案例地比较“BUSSE”和“Buße”。见鬼，您可能还想比较“BUSSE”和“BUẞE”相等——这是较新的大写形式。推荐使用casefold:

str.casefold () 返回字符串的大小写折叠副本。折叠的字符串可用于 caseless匹配。 大小写折叠类似于小写，但更激进，因为它是 用于删除字符串中的所有大小写区别。[…]

不要只使用lower。如果casefold不可用，执行.upper().lower()会有所帮助(但只是略有帮助)。

然后你应该考虑口音。如果你的字体渲染器很好，你可能认为“ê”==“ê”-但它不是:

>>> "ê" == "ê"
False

这是因为后者的重音是一个组合字符。

>>> import unicodedata
>>> [unicodedata.name(char) for char in "ê"]
['LATIN SMALL LETTER E WITH CIRCUMFLEX']
>>> [unicodedata.name(char) for char in "ê"]
['LATIN SMALL LETTER E', 'COMBINING CIRCUMFLEX ACCENT']

最简单的处理方法是unicodedata.normalize。您可能希望使用NFKD规范化，但请随意查看文档。然后有人会这么做

>>> unicodedata.normalize("NFKD", "ê") == unicodedata.normalize("NFKD", "ê")
True

最后，这里用函数表示:

import unicodedata

def normalize_caseless(text):
    return unicodedata.normalize("NFKD", text.casefold())

def caseless_equal(left, right):
    return normalize_caseless(left) == normalize_caseless(right)

from re import search, IGNORECASE

def is_string_match(word1, word2):
    #  Case insensitively function that checks if two words are the same
    # word1: string
    # word2: string | list

    # if the word1 is in a list of words
    if isinstance(word2, list):
        for word in word2:
            if search(rf'\b{word1}\b', word, IGNORECASE):
                return True
        return False

    # if the word1 is same as word2
    if search(rf'\b{word1}\b', word2, IGNORECASE):
        return True
    return False

is_match_word = is_string_match("Hello", "hELLO") 
True

is_match_word = is_string_match("Hello", ["Bye", "hELLO", "@vagavela"])
True

is_match_word = is_string_match("Hello", "Bye")
False