python split space

发现自己写python的空格split还挺多坎的，尤其是最后一个是空格的情形：

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

def split(s):     i = 0     ans = []     while i < len(s):         start = i         # find space         while i < len(s) and s[i] != ' ':             i += 1         ans.append(s[start:i])         i += 1     if s and s[-1] == " ":         ans.append("")     return ans   assert split("") == [] assert split(" ") == ["", ""] assert split("  ") == ["", "", ""] assert split("a") == ["a"] assert split("a b") == ["a", "b"] assert split(" a") == ["", "a"] assert split("a ") == ["a", ""] assert split(" a b") == ["", "a", "b"] assert split("a b ") == ["a", "b", ""] assert split("ac bcd") == ["ac", "bcd"]