Python实现大文件排序的方法
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2022-04-23 11:28:04
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本文实例讲述了Python实现大文件排序的方法。分享给大家供大家参考。具体实现方法如下：
import gzip
import os
from multiprocessing import Process, Queue, Pipe, current_process, freeze_support
from datetime import datetime
def sort_worker(input,output):
while True:
lines = input.get().splitlines()
element_set = {}
for line in lines:
if line.strip() == 'STOP':
return
try:
element = line.split(' ')[0]
if not element_set.get(element): element_set[element] = ''
except:
pass
sorted_element = sorted(element_set)
#print sorted_element
output.put('\n'.join(sorted_element))
def write_worker(input, pre):
os.system('mkdir %s'%pre)
i = 0
while True:
content = input.get()
if content.strip() == 'STOP':
return
write_sorted_bulk(content, '%s/%s'%(pre, i))
i += 1
def write_sorted_bulk(content, filename):
f = file(filename, 'w')
f.write(content)
f.close()
def split_sort_file(filename, num_sort = 3, buf_size = 65536*64*4):
t = datetime.now()
pre, ext = os.path.splitext(filename)
if ext == '.gz':
file_file = gzip.open(filename, 'rb')
else:
file_file = open(filename)
bulk_queue = Queue(10)
sorted_queue = Queue(10)
NUM_SORT = num_sort
sort_worker_pool = []
for i in range(NUM_SORT):
sort_worker_pool.append( Process(target=sort_worker, args=(bulk_queue, sorted_queue)) )
sort_worker_pool[i].start()
NUM_WRITE = 1
write_worker_pool = []
for i in range(NUM_WRITE):
write_worker_pool.append( Process(target=write_worker, args=(sorted_queue, pre)) )
write_worker_pool[i].start()
buf = file_file.read(buf_size)
sorted_count = 0
while len(buf):
end_line = buf.rfind('\n')
#print buf[:end_line+1]
bulk_queue.put(buf[:end_line+1])
sorted_count += 1
if end_line != -1:
buf = buf[end_line+1:] + file_file.read(buf_size)
else:
buf = file_file.read(buf_size)
for i in range(NUM_SORT):
bulk_queue.put('STOP')
for i in range(NUM_SORT):
sort_worker_pool[i].join()
for i in range(NUM_WRITE):
sorted_queue.put('STOP')
for i in range(NUM_WRITE):
write_worker_pool[i].join()
print 'elasped ', datetime.now() - t
return sorted_count
from heapq import heappush, heappop
from datetime import datetime
from multiprocessing import Process, Queue, Pipe, current_process, freeze_support
import os
class file_heap:
def __init__(self, dir, idx = 0, count = 1):
files = os.listdir(dir)
self.heap = []
self.files = {}
self.bulks = {}
self.pre_element = None
for i in range(len(files)):
file = files[i]
if hash(file) % count != idx: continue
input = open(os.path.join(dir, file))
self.files[i] = input
self.bulks[i] = ''
heappush(self.heap, (self.get_next_element_buffered(i), i))
def get_next_element_buffered(self, i):
if len(self.bulks[i]) 1024:
self.q.put(self.wbuf)
self.wbuf = []
def diff_file(file_old, file_new, file_diff, buf = 268435456):
print 'buffer size', buf
from file_split import split_sort_file
os.system('rm -rf '+ os.path.splitext(file_old)[0] )
os.system('rm -rf '+ os.path.splitext(file_new)[0] )
t = datetime.now()
split_sort_file(file_old,5,buf)
split_sort_file(file_new,5,buf)
print 'split elasped ', datetime.now() - t
os.system('cat %s/* | wc -l'%os.path.splitext(file_old)[0])
os.system('cat %s/* | wc -l'%os.path.splitext(file_new)[0])
os.system('rm -f '+file_diff)
t = datetime.now()
zdiff = open(file_diff, 'a')
old_q = Queue(1024)
new_q = Queue(1024)
old_queue = queue_buffer(old_q)
new_queue = queue_buffer(new_q)
h1 = Process(target=heappoppush2, args=(os.path.splitext(file_old)[0], old_queue, 3))
h2 = Process(target=heappoppush2, args=(os.path.splitext(file_new)[0], new_queue, 3))
h1.start(), h2.start()
old = old_queue.get()
new = new_queue.get()
old_count, new_count = 0, 0
while old is not None or new is not None:
if old > new or old is None:
zdiff.write(' '+old+'\n')
old = old_queue.get()
old_count +=1
else:
old = old_queue.get()
new = new_queue.get()
print 'new_count:', new_count
print 'old_count:', old_count
print 'diff elasped ', datetime.now() - t
h1.join(), h2.join()
希望本文所述对大家的Python程序设计有所帮助。
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