Looping through list for a pattern match with strings with wildcards

Question

I have sample code of a function in which uses pattern matching to match a string value containing wildcards with an actual string value.

def isMatch(text, pattern):
    n = len(text)
    m = len(pattern)
    i = 0
    j = 0
    startIndex = -1
    match = 0

    while i < n:
        if j < m and (pattern[j] == '?' or pattern[j] == text[i]):
            i += 1
            j += 1
        elif j < m and pattern[j] == '*':
            startIndex = j
            match = i
            j += 1
        elif startIndex != -1:
            j = startIndex + 1
            match += 1
            i = match
        else:
            return False

    while j < m and pattern[j] == '*':
        j += 1

    return j == m


s = "RE340T6-1MCWW"
p = "RE340T*-*****"

if isMatch(s, p):
    print("Yes")
else:
    print("No")

In this sample code, the string (s) "RE340T6-1MCWW" matches the pattern (p), "RE340T*-*****" and returns a "Yes", as it should.

What I want to do is using the above function,have a list of strings and find the matches in a list of strings with wildcards. For example:

s = ['GUC 40 410','HUC 40 410','XUC 40 410']
p = ['GUC 40 4**','HUC 40 4**','XUC 40 4**']

I don't know how to insert looping through the lists in the function to return where the string (s) matches the pattern (p). Any ideas for the next step?

If I just substitute the list for the static string, it just returns a "No"

Answer 1

You can simply use another _find method to check for isMatch():

def isMatch(text, pattern):
    n, m = len(text), len(pattern)
    i, j = 0, 0
    startIndex = -1
    match = 0

    while i < n:
        if j < m and (pattern[j] == '?' or pattern[j] == text[i]):
            i += 1
            j += 1
        elif j < m and pattern[j] == '*':
            startIndex = j
            match = i
            j += 1
        elif startIndex != -1:
            j = startIndex + 1
            match += 1
            i = match
        else:
            return False

    while j < m and pattern[j] == '*':
        j += 1

    return j == m


def _find(S, ps):
    res = []
    for i, s in enumerate(S):
        for j, p in enumerate(ps):
            if isMatch(s, p):
                res.append((i, j))
    return res


s = ['GUC 40 410', 'HUC 40 410', 'XUC 40 410']
p = ['GUC 40 4**', 'HUC 40 4**', 'XUC 40 4**']

print(_find(s, p))

Prints

[(0, 0), (1, 1), (2, 2)]