unwind的答案适用于小文件。如果你想要一个通用的解决方案,坚持迭代器和生成器。
您可以定义一个生成器函数,它可以生成line_i,line_i + 3和line_i + 4的元组。
随着进口
from collections import deque
from itertools import islice
我们可以定义一个新的发电机功能:
def reflexive_zip(iterator, offset = 0):
offset = int(offset)
if offset == 0:
for element in iterator:
yield (element, element)
else:
d = deque(islice(iterator,abs(offset)))
for element in iterator:
d.append(element)
if offset < 0:
yield (element, d.popleft())
else:
yield (d.popleft(), element)
它需要一个iterator
,创建使用iterator
的元件的deque
和产量的元组的一些缓冲。偏移量可以通过参数offset
进行控制。
这是完整的脚本。使用示例在主要部分。
if __name__ == "__main__":
from cStringIO import StringIO
f = StringIO("""Header 1
line 1
line 2
line 3
line 4
Header 2
line 1
line 2
line 3
line 4""")
#for line, other_line in reflexive_zip(f, 4):
# print "%s -> %s" %(line, other_line)
for ((line, _ignore),(line3, line4)) in reflexive_zip(reflexive_zip(f,1),3):
print "%s -> %s %s" %(line, line3, line4)
from collections import deque
from itertools import islice
def reflexive_zip(iterator, offset = 0):
offset = int(offset)
if offset == 0:
for element in iterator:
yield (element, element)
else:
d = deque(islice(iterator,abs(offset)))
for element in iterator:
d.append(element)
if offset < 0:
yield (element, d.popleft())
else:
yield (d.popleft(), element)
if __name__ == "__main__":
from cStringIO import StringIO
f = StringIO("""Header 1
line 1
line 2
line 3
line 4
Header 2
line 1
line 2
line 3
line 4""")
#for line, other_line in reflexive_zip(f, 4):
# print "%s -> %s" %(line, other_line)
for ((line, _ignore),(line3, line4)) in reflexive_zip(reflexive_zip(f,1),3):
print "%s -> %s %s" %(line, line3, line4)
输出:
Header 1
-> line 3
line 4
line 1
-> line 4
Header 2
line 2
-> Header 2
line 1
line 3
-> line 1
line 2
line 4
-> line 2
line 3
Header 2
-> line 3
line 4
你有什么这么远吗?它在做什么,它不应该?或缺少哪些部分? – thegrinner 2013-02-08 13:15:44
目前还不清楚你的意思是不同的背景。 – LtWorf 2013-02-08 13:28:52
这个问题看起来很像这个:http://stackoverflow.com/q/14742446/989121 – georg 2013-02-08 13:44:42