71. Simplify Path

Given an absolute path for a file (Unix-style), simplify it.

For example,
path = "/home/", => "/home"
path = "/a/./b/../../c/", => "/c"
path = "/a/../../b/../c//.//", => "/c"
path = "/a//b////c/d//././/..", => "/a/b/c"

In a UNIX-style file system, a period ('.') refers to the current directory, so it can be ignored in a simplified path. Additionally, a double period ("..") moves up a directory, so it cancels out whatever the last directory was. For more information, look here: https://en.wikipedia.org/wiki/Path_(computing)#Unix_style

Corner Cases:

Did you consider the case where path = "/../"?
In this case, you should return "/".
Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/".
In this case, you should ignore redundant slashes and return "/home/foo".

Solution1:

class Solution:
    def simplifyPath(self, path):
        """
        :type path: str
        :rtype: str
        """
        res = []
        p = path.split('/')
        for i in p:
            if i=='' or i=='.':
                continue
            if i=='..':
                if len(res):
                   res.pop()
                continue
            res.append(i)
        return '/'+'/'.join(res) #join的用法

Solution2:

class Solution:
    def simplifyPath(self, path):
        """
        :type path: str
        :rtype: str
        """
        return os.path.realpath(path)