在python环境中提供两种排序方案：用库函数sorted()对字符串排序，它的对象是字符；用函数sort()对数字排序，它的对象是数字，如果读取文件的话，需要进行处理(把文件后缀名‘屏蔽')。

(1)首先：我测试的文件夹是/img/，里面的文件都是图片，如下图所示：

(2)测试库函数sorted()，直接贴出代码：

import numpy as np

import os

img_path='./img/'

img_list=sorted(os.listdir(img_path))#文件名按字母排序

img_nums=len(img_list)

for i in range(img_nums):

img_name=img_path+img_list[i]

print(img_name)

运行效果如下：

从图片可以清晰的看出，文件名是按字符排序的。

(3)测试函数sort()，代码：

import numpy as np

import os

img_path='./img/'

img_list=os.listdir(img_path)

img_list.sort()

img_list.sort(key = lambda x: int(x[:-4])) ##文件名按数字排序

img_nums=len(img_list)

for i in range(img_nums):

img_name=img_path+img_list[i]

print(img_name)

运行效果如下：

可以看出，文件名是按数字排序的；顺便提下，sort函数中用到了匿名函数(key = lambda x:int(x[:-4]))，其作用是将后缀名'.jpg'“屏蔽”(因为‘.jpg'是4个字符，所以[:-4]的含义是从文件名开始到倒数第四个字符为止)，具体看python的匿名函数和数组取值方式。

实例扩展：

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]) < 256:

if self.files[i] is not None:

buf = self.files[i].read(65536)

if buf:

self.bulks[i] += buf

else:

self.files[i].close()

self.files[i] = None

end_line = self.bulks[i].find('\n')

if end_line == -1:

end_line = len(self.bulks[i])

element = self.bulks[i][:end_line]

self.bulks[i] = self.bulks[i][end_line+1:]

return element

def poppush_uniq(self):

while True:

element = self.poppush()

if element is None:

return None

if element != self.pre_element:

self.pre_element = element

return element

def poppush(self):

try:

element, index = heappop(self.heap)

except IndexError:

return None

new_element = self.get_next_element_buffered(index)

if new_element:

heappush(self.heap, (new_element, index))

return element

def heappoppush(dir, queue, idx = 0, count = 1):

heap = file_heap(dir, idx, count)

while True:

d = heap.poppush_uniq()

queue.put(d)

if d is None: return

def heappoppush2(dir, queue, count = 1):

heap = []

procs = []

queues = []

pre_element = None

for i in range(count):

q = Queue(1024)

q_buf = queue_buffer(q)

queues.append(q_buf)

p = Process(target=heappoppush, args=(dir, q_buf, i, count))

procs.append(p)

p.start()

queues = tuple(queues)

for i in range(count):

heappush(heap, (queues[i].get(), i))

while True:

try:

d, i= heappop(heap)

except IndexError:

queue.put(None)

for p in procs:

p.join()

return

else:

if d is not None:

heappush(heap,(queues[i].get(), i))

if d != pre_element:

pre_element = d

queue.put(d)

def merge_file(dir):

heap = file_heap( dir )

os.system('rm -f '+dir+'.merge')

fmerge = open(dir+'.merge', 'a')

element = heap.poppush_uniq()

fmerge.write(element+'\n')

while element is not None:

element = heap.poppush_uniq()

fmerge.write(element+'\n')

class queue_buffer:

def __init__(self, queue):

self.q = queue

self.rbuf = []

self.wbuf = []

def get(self):

if len(self.rbuf) == 0:

self.rbuf = self.q.get()

r = self.rbuf[0]

del self.rbuf[0]

return r

def put(self, d):

self.wbuf.append(d)

if d is None or len(self.wbuf) > 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('< '+new+'\n')

new = new_queue.get()

new_count +=1

elif old < new or new 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()

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