获取两个符号之间的特定字母

def get_letters_between_symbols(string, symbol1, symbol2, target_letter):
    start_index = -1
    end_index = -1
    result = ""

    for i in range(len(string)):
        if string[i] == symbol1:
            start_index = i
        elif string[i] == symbol2:
            end_index = i
            break

    if start_index != -1 and end_index != -1:
        for i in range(start_index + 1, end_index):
            if string[i] == target_letter:
                result += string[i]

    return result

string = "abcde(fg)hi(jk)lmn"
symbol1 = "("
symbol2 = ")"
target_letter = "g"

result = get_letters_between_symbols(string, symbol1, symbol2, target_letter)
print(result)  # 输出：g