如何使用Python对大型文件进行排序? [英] How to sort huge files with Python?
问题描述
我在activestate.com上找到了一些有前途的代码来对大型文件进行排序.我正在尝试在Ubuntu 10.04的默认Python 2.6.5解释器上运行它.当我尝试在一个小的测试文件上运行它时,出现以下错误跟踪.我在activestate.com上寻求帮助,但是该线程已经沉默了18个月以上.这里有没有人看到明显的解决方案?
I found some this promising code on activestate.com to sort huge files. I'm trying to run it on the default Python 2.6.5 interpreter on Ubuntu 10.04. When I try running it on a small test file, I get the error trace below. I asked for help on activestate.com, but this thread has been silent for over 18 months. Is there anyone here who sees an obvious solution?
谢谢.
## {{{ http://code.activestate.com/recipes/576755/ (r3)
# based on Recipe 466302: Sorting big files the Python 2.4 way
# by Nicolas Lehuen
import os
from tempfile import gettempdir
from itertools import islice, cycle
from collections import namedtuple
import heapq
Keyed = namedtuple("Keyed", ["key", "obj"])
def merge(key=None, *iterables):
# based on code posted by Scott David Daniels in c.l.p.
# http://groups.google.com/group/comp.lang.python/msg/484f01f1ea3c832d
if key is None:
keyed_iterables = iterables
else:
keyed_iterables = [(Keyed(key(obj), obj) for obj in iterable)
for iterable in iterables]
for element in heapq.merge(*keyed_iterables):
yield element.obj
def batch_sort(input, output, key=None, buffer_size=32000, tempdirs=None):
if tempdirs is None:
tempdirs = []
if not tempdirs:
tempdirs.append(gettempdir())
chunks = []
try:
with open(input,'rb',64*1024) as input_file:
input_iterator = iter(input_file)
for tempdir in cycle(tempdirs):
current_chunk = list(islice(input_iterator,buffer_size))
if not current_chunk:
break
current_chunk.sort(key=key)
output_chunk = open(os.path.join(tempdir,'%06i'%len(chunks)),'w+b',64*1024)
chunks.append(output_chunk)
output_chunk.writelines(current_chunk)
output_chunk.flush()
output_chunk.seek(0)
with open(output,'wb',64*1024) as output_file:
output_file.writelines(merge(key, *chunks))
finally:
for chunk in chunks:
try:
chunk.close()
os.remove(chunk.name)
except Exception:
pass
错误跟踪:
Traceback (most recent call last):
File "./batch_sort.py", line 108, in <module>
batch_sort(args[0],args[1],options.key,options.buffer_size,options.tempdirs)
File "./batch_sort.py", line 54, in batch_sort
output_file.writelines(merge(key, *chunks))
File "./batch_sort.py", line 30, in merge
yield element.obj
AttributeError: 'str' object has no attribute 'obj'
推荐答案
用于合并的代码不正确. 如果您不提供键,则每个元素都是字符串,而不是带键的元组.
The code for merge is incorrect. If you don't provide a key, each element is a string instead of a keyed tuple.
尝试以下方法:
def merge(key=None, *iterables):
# based on code posted by Scott David Daniels in c.l.p.
# http://groups.google.com/group/comp.lang.python/msg/484f01f1ea3c832d
if key is None:
for element in heapq.merge(*iterables):
yield element
else:
keyed_iterables = [(Keyed(key(obj), obj) for obj in iterable)
for iterable in iterables]
for element in heapq.merge(*keyed_iterables):
yield element.obj
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