python list分组操作--简便易

#!/usr/bin/python
L = [3,8,9,4,1,10,6,7,2,5]
result = [[],[],[]]
for item in L:
        if len(result[0]) < 3:
                result[0].append(item)
        elif len(result[1]) < 3:
                result[1].append(item)
        else:
                result[2].append(item)
print result

a=[1,2,3,4,5,6,7,8,9,10,11,12,13,14]
for i in range(0, len(a), 3):
    b.append(a[i:i+3])
print b

print [a[i:i+3] for i in xrange(0,len(a),3)]