Python: 查找包含通配符的字符串中是否存在子字符串

Question

我想创建一个接受两个输入的函数，fullstring 和 substring。如果子字符串存在于完整字符串中，函数应该 return True。否则，它将return False。如果子字符串包含通配符 (*)，则通配符可以表示任何单个字符。

例如：

arg1: fullstring = "hitherehello"
arg2: substring = "the*e
output: True

我尝试过的：下面是一个匹配子字符串和父字符串的函数，但我似乎无法弄清楚如何整合通配符。

def count_substring(string, sub_string):
    len_ss = len(sub_string)
    for i in range(len(string) - len_ss + 1):
        if string[i:i+len_ss] == sub_string:
            return True

    return False

约束条件：我不能使用正则表达式或内置 python 函数，例如 find.

Answer 1

您可以查找字符串中的每个 'wildcard' 部分，return 位置，然后检查是否跟进：

def count_substring(string, sub_string, lastIndex):
    len_ss = len(sub_string)
    for i in range(len(string) - len_ss + 1):
        if string[i:i + len_ss] == sub_string and lastIndex < i + len_ss:
            return i + len_ss
    return -1


def count_wrapper(string, sub_string, index):
    positions = []
    for wild_sub_string in sub_string.split('*'):
        index = count_substring(string, wild_sub_string, index)
        positions.append(index)
    # check pairwise
    return all([x + 2 == y for x, y in zip(*[iter(positions)] * 2)])


print(count_wrapper("there", "the*e", 0))
print(count_wrapper("thera", "the*e", 0))
print(count_wrapper("theresa", "the*e*a", 0))

输出：

True
False
True

Answer 2

def search(fullstring, substring):
    def check(s1, s2):
        for a, b in zip(s1, s2):
            if a != b and b != "*":
                return False
        return True

    for i in range(len(fullstring) - len(substring) + 1):
        if check(fullstring[i : i + len(substring)], substring):
            return True

    return False


print(search("hitherehello", "the*e"))

打印：

True

更多测试：

print(search("hiXherehello", "*he*e")) # True
print(search("hitherXhello", "the*e")) # False

Answer 3

这似乎对我有用：

def check_all_substrings(index, string, substrings):
    for ss in substrings:
        if string[index:index+len(ss)] != ss:
            return False

        # If we matched, move the index along by the length of the substring + 1, so we skip a character
        index = index + len(ss) + 1
    return True

def match(string, substring):
    i = 0
    substrings = substring.split('*')

    while (i < (len(string) - len(substring))):

        if check_all_substrings(i, string, substrings):
            return True

        i += 1

    return False

# match substring
assert match("hitherehello", "there")

#match substring with 1 wild card
assert match("hitherehello", "the*e") 

# match 
assert match("hithat", "h*t*a")

# wild cards should match exactly 1 character
assert not match("hitherrrrehello", "the*e")

# do not match invalid substrings
assert not match("hithat", "the*e")
assert not match("hithat", "there")

Python: 查找包含通配符的字符串中是否存在子字符串

Python: Find If Substring Exists in String Including Wildcard

python

string

algorithm

string-matching

data-structures