929. Unique Email Addresses and 709. To Lower Case

Every email consists of a local name and a domain name, separated by the @ sign.

For example, in [email protected], alice is the local name, and leetcode.com is the domain name.

Besides lowercase letters, these emails may contain '.'s or '+'s.

If you add periods ('.') between some characters in the local name part of an email address, mail sent there will be forwarded to the same address without dots in the local name.  For example, "[email protected]" and "[email protected]" forward to the same email address.  (Note that this rule does not apply for domain names.)

If you add a plus ('+') in the local name, everything after the first plus sign will be ignored. This allows certain emails to be filtered, for example [email protected] will be forwarded to [email protected].  (Again, this rule does not apply for domain names.)

It is possible to use both of these rules at the same time.

Given a list of emails, we send one email to each address in the list.  How many different addresses actually receive mails? 

Example 1:

Input: ["[email protected]","[email protected]","[email protected]"]
Output: 2
Explanation: "[email protected]" and "[email protected]" actually receive mails

 

Note:

• 1 <= emails[i].length <= 100
• 1 <= emails.length <= 100
• Each emails[i] contains exactly one '@' character.

class Solution:
    def numUniqueEmails(self, emails):
        """
        :type emails: List[str]
        :rtype: int
        """
        
        results =set() // 注意：创建一个空集合必须用 set() 而不是 { }，因为 { } 是用来创建一个空字典。
        for email in emails:
            local, _, domain = email.partition('@')
            if '+' in local:
                local = local[:local.index('+')]
            results.add(local.replace('.','') + '@' + domain)
        return len(results)

集合（set）是一个无序的不重复元素序列。

可以使用大括号 { } 或者 set() 函数创建集合，注意：创建一个空集合必须用 set() 而不是 { }，因为 { } 是用来创建一个空字典。

Reference：

Partition Method   http://www.runoob.com/python/att-string-partition.html

Index Method        http://www.runoob.com/python3/python3-string-index.html

Replace Method   http://www.runoob.com/python3/python3-string-replace.html

Set                         http://www.runoob.com/python3/python3-set.html

 

 

 

709. To Lower Case

Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase.

 

Example 1:

Input: "Hello"
Output: "hello"

Example 2:

Input: "here"
Output: "here"

Example 3:

Input: "LOVELY"
Output: "lovely"

 

class Solution:
    def toLowerCase(self, str):
        """
        :type str: str
        :rtype: str
        """
        return str.lower()