python 字符串转换，如：IloveYOUmoreTHANiCANsay=>I love you more than i can say`

python
def sep_words(s):
    '''

    ret = s[0].upper()
    for i in range(1, len(s)):
    # 检测字符串是否小写组成等于下个元素是否大写组成
        if s[i].islower() == s[i-1].isupper():
            ret += ' '
        ret += s[i].lower()
    return ret  #方法一
    '''
    '''
    # 方法二
    ret = s[0]
    for i in range(1, len(s)):
        if s[i].islower() == s[i-1].isupper():
            ret += ' '
        ret += s[i]
    return ret.capitalize()
    '''
    方法三
    ret = ''
    for i in range(len(s)-1):
        ret += s[i]
        if s[i].islower() == s[i+1].isupper():
            ret += ' '
    #将最后一个元素添加进去
    ret += s[-1]
    return ret.capitalize()


print(sep_words('IloveYOUmoreTHANiCANsay')