像下面的那样，基本思路是直接长度除分数得到每份的长度，如果有余数的话前余数份长度各加1。avsplit1看上去比avsplit2要pythonic 一些，但是性能方面avsplit2好点。

Pythons = 'abcdefghijklmn'
n = 5



def avsplit1(s, n):
    fn = len(s)//n
    rn = len(s)%n
    ar = [fn+1]*rn+ [fn]*(n-rn)
    si = [i*(fn+1) if i<rn else (rn*(fn+1)+(i-rn)*fn) for i in xrange(n)]
    sr = [s[si[i]:si[i]+ar[i]] for i in xrange(n)]
    return sr

def avsplit2(s, n):
    fn = len(s)//n
    rn = len(s)%n
    sr = []
    ix = 0
    for i in xrange(n):
        if i<rn:
            sr.append(s[ix:ix+fn+1])
            ix += fn+1
        else:
            sr.append(s[ix:ix+fn])
            ix += fn
    return sr

print avsplit1(s,n)
print avsplit2(s,n)

    s = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    n = 3
    print([s[i:i+n] for i in xrange(0, len(s), n)])
    #['ABC', 'DEF', 'GHI', 'JKL', 'MNO', 'PQR', 'STU', 'VWX', 'YZ']

pythondef segmented(iterable):
    def _seg(width):
        it = iterable
        while len(it) > width:
            yield it[:width]
            it = it[width:]
        yield it

    return _seg

python>>> s = 'asdfghji'
>>> split_every = segmented(s)
>>> print(list(split_every(2)))
['as', 'df', 'gh', 'ji']
>>> print(list(split_every(3)))
['asd', 'fgh', 'ji']
>>> print(s)
asdfghji