python⽂件排序的⽅法总结
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 os
from multiprocessing import Process, Queue, Pipe, current_process, freeze_support
from datetime import datetime
def sort_worker(input,output):
while True:
lines = ().splitlines()
element_set = {}
for line in lines:
if line.strip() == 'STOP':
return
try:
element = line.split(' ')[0]
if not (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 = ()
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 = w()
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 = ad(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:] + ad(buf_size)
else:
buf = ad(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 ', w() - t
return sorted_count
from heapq import heappush, heappop
from datetime import datetime
from multiprocessing import Process, Queue, Pipe, current_process, freeze_support
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, (_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 = _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
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 = ()
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 = w()
split_sort_file(file_old,5,buf)
split_sort_file(file_new,5,buf)
print 'split elasped ', w() - 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 = w()
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 = ()
new = ()
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_count +=1
elif old < new or new is None:
zdiff.write('> '+old+'\n')
old = ()
old_count +=1
else:
merge函数
old = ()
new = ()
print 'new_count:', new_count
print 'old_count:', old_count
print 'diff elasped ', w() - t
h1.join(), h2.join()
到此这篇关于python⽂件排序的⽅法总结的⽂章就介绍到这了，更多相关python⽂件排序都有哪些⽅法内容请搜索以前的⽂章或继续浏览下⾯的相关⽂章希望⼤家以后多多⽀持！

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