python之是否有更优雅/pythonic 的方式来表达这种结构

itemList = ["a","b","c","d","e","f","g","h"] 
aa = "NULL" 
bb = "NULL" 
cc = "NULL" 
for item in itemList: 
    aa = bb 
    bb = cc 
    cc = item 
    if aa == "NULL": 
        continue 
    print "%s_%s_%s" % (aa, bb, cc) 

请您参考如下方法:

>>> ['_'.join(itemList[i:i+3]) for i in range(len(itemList)-2)] 
['a_b_c', 'b_c_d', 'c_d_e', 'd_e_f', 'e_f_g', 'f_g_h'] 

或者如果你坚持打印:

>>> for i in range(len(itemList)-2): 
    print('_'.join(itemList[i:i+3]))