如何在Python中以不区分大小写的方式比较字符串?

我想使用简单的python代码将常规字符串的比较封装到存储库字符串中。我也想有能力在字典中查找值哈希字符串使用常规的python字符串。


当前回答

考虑使用jaraco.text中的FoldedCase:

>>> from jaraco.text import FoldedCase
>>> FoldedCase('Hello World') in ['hello world']
True

如果你想要一个不考虑大小写的字典,使用来自jaraco.collections的FoldedCaseKeyedDict:

>>> from jaraco.collections import FoldedCaseKeyedDict
>>> d = FoldedCaseKeyedDict()
>>> d['heLlo'] = 'world'
>>> list(d.keys()) == ['heLlo']
True
>>> d['hello'] == 'world'
True
>>> 'hello' in d
True
>>> 'HELLO' in d
True

其他回答

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

Unicode标准的第3.13节定义了无大小写的算法 匹配。

X.casefold() == Python 3中的Y.casefold()实现了“默认的无大小写匹配”(D144)。

案例折叠不会在所有实例中保存字符串的规范化,因此需要进行规范化('å' vs。“一个”)。D145引入了“规范无大小写匹配”:

import unicodedata

def NFD(text):
    return unicodedata.normalize('NFD', text)

def canonical_caseless(text):
    return NFD(NFD(text).casefold())

对于涉及U+0345字符的非常罕见的边缘情况,NFD()被调用两次。

例子:

>>> 'å'.casefold() == 'å'.casefold()
False
>>> canonical_caseless('å') == canonical_caseless('å')
True

此外,还有兼容无案例匹配(D146),如“mhz”(U+3392)和“标识符无案例匹配”,以简化和优化标识符的无案例匹配。

这是另一个正则表达式,我已经学会了爱/恨在过去的一周,所以通常导入(在这种情况下是),反映了我的感受! 做一个正常的函数....征求意见,然后使用....东西= re.compile垃圾邮件(r 'foo * | *’,是的)……re.I(是的。我下面)是相同的IGNORECASE,但你不能犯很多错误写它!

然后你使用正则表达式搜索你的消息,但老实说,这应该是在自己的几页,但重点是,foo或垃圾邮件管道在一起,大小写被忽略。 然后,如果找到其中任何一个,lost_n_found将显示其中一个。如果都不是,则lost_n_found等于None。如果它不等于none,则使用return lost_n_find .lower()返回小写的user_input

这让你更容易匹配任何区分大小写的东西。最后(NCS)代表“没有人认真关心……!”或不区分大小写....无论哪种

如果有人有任何问题,请问我。

    import re as yes

    def bar_or_spam():

        message = raw_input("\nEnter FoO for BaR or SpaM for EgGs (NCS): ") 

        message_in_coconut = yes.compile(r'foo*|spam*',  yes.I)

        lost_n_found = message_in_coconut.search(message).group()

        if lost_n_found != None:
            return lost_n_found.lower()
        else:
            print ("Make tea not love")
            return

    whatz_for_breakfast = bar_or_spam()

    if whatz_for_breakfast == foo:
        print ("BaR")

    elif whatz_for_breakfast == spam:
        print ("EgGs")

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.
def search_specificword(key, stng):
    key = key.lower()
    stng = stng.lower()
    flag_present = False
    if stng.startswith(key+" "):
        flag_present = True
    symb = [',','.']
    for i in symb:
        if stng.find(" "+key+i) != -1:
            flag_present = True
    if key == stng:
        flag_present = True
    if stng.endswith(" "+key):
        flag_present = True
    if stng.find(" "+key+" ") != -1:
        flag_present = True
    print(flag_present)
    return flag_present

输出: search_specificword(“经济适用房”,“欧洲经济适用房的核心”) 假

search_specificword(“经济适用房”,“经济适用房的核心,在欧洲”) 真正的