两条Python2.7随机播放从不编译的程序

Question

我对Python（和一般编程）比较陌生，但需要解决这个问题。我试图用不同的规则将csv文件中的信息随机化（这不是家庭作业，是为了工作）。我以前有过这个脚本的版本，所以我知道基本的都可以。然而，在当前的两个版本中，它们永远不会成功。我将在下面包括相关的代码位。你知道吗

    import os
import sys
import random
import csv

# Opens the file supplied in the first argument in the command line.
# Then, sets up each row as its own entity for later randomization
with open(os.path.join(os.getcwd(),sys.argv[1]),'rU') as csvfile:
    orderimport = csv.reader(csvfile, dialect=csv.excel_tab, delimiter=',')
    orderdata = []

    next(orderimport,None)
    for row in orderimport:
        orderdata.append(row)

done = False
attempt = 1
max_i = 0

while not done:
    random.shuffle(orderdata)
    done = True; # maybe

# prints the attempts in hundreds of thousands, as well as the max number of lines completed before starting over (however many rows are in the sheet is the max)

    if attempt % 100000 == 0:
        print attempt,max_i
    for i in range(len(orderdata)-3):

# This is where you supply the rules!
# This is useful if you want to prevent blocks of trials. You can change these values to whatever you need sorted. 
        if (orderdata[i][11]==orderdata[i+1][11] and orderdata[i][11]==orderdata[i+2][11] and orderdata[i][11]==orderdata[i+3][11]) or \
        (orderdata[i][6]==orderdata[i+1][6]):
            if i>max_i:
                max_i = i
            done = False
            break
        else:           
            continue
    attempt += 1
# This is where it will saves the file. Do not change this part! 
# Just supply the full desired filename (with file type) as the second argument when running the script.
with open(os.path.join(os.getcwd(),sys.argv[2]),'wb') as csvfile:
    orderexport = csv.writer(csvfile, dialect=csv.excel_tab, delimiter=',')
    for row in orderdata:
        orderexport.writerow(row)

还有一个稍微不同的程序，只是列出了不同的部分：

    if abs(int(orderdata[i][5]) - int(orderdata[i+1][5])) < 2 and abs(int(orderdata[i][6]) - int(orderdata[i+1][6])) < 2:
        if i>max_i:
            max_i = i
        done = False
        break
    else:           
        continue
attempt += 1

这两种方法都有效，但只要不断前进，就永远找不到符合这些规则的随机列表。我是在做傻事，还是根本不可能？谢谢！你知道吗

Answer 1

下面是一种通过修剪和回溯探索所有可能的行顺序的方法。在本例中，我们感兴趣的是一个排序，其中a[i][2] <> a[i+1][2]表示所有i。你知道吗

def sols(a,avail,avoid):
  if not avail:
    yield []
  for i in avail:
    r = a[i]
    if not (avoid and r[2] == avoid):     to see all orderings, change to "if True:"
      avail1 = avail - set([i])
      for s in sols(a, avail1, r[2]):
        yield [r]+s

def solutions(a):
  inds = range(0, len(a))
  return sols(a, set(inds), None)

arr = [ [1,1,10,1,1], [2,2,30,2,2], [3,3,10,3,3], [4,4,30,4,4] ]
for s in solutions(arr):
  print s

输出为：

[[1, 1, 10, 1, 1], [2, 2, 30, 2, 2], [3, 3, 10, 3, 3], [4, 4, 30, 4, 4]]
[[1, 1, 10, 1, 1], [4, 4, 30, 4, 4], [3, 3, 10, 3, 3], [2, 2, 30, 2, 2]]
[[2, 2, 30, 2, 2], [1, 1, 10, 1, 1], [4, 4, 30, 4, 4], [3, 3, 10, 3, 3]]
[[2, 2, 30, 2, 2], [3, 3, 10, 3, 3], [4, 4, 30, 4, 4], [1, 1, 10, 1, 1]]
[[3, 3, 10, 3, 3], [2, 2, 30, 2, 2], [1, 1, 10, 1, 1], [4, 4, 30, 4, 4]]
[[3, 3, 10, 3, 3], [4, 4, 30, 4, 4], [1, 1, 10, 1, 1], [2, 2, 30, 2, 2]]
[[4, 4, 30, 4, 4], [1, 1, 10, 1, 1], [2, 2, 30, 2, 2], [3, 3, 10, 3, 3]]
[[4, 4, 30, 4, 4], [3, 3, 10, 3, 3], [2, 2, 30, 2, 2], [1, 1, 10, 1, 1]]

请注意，在4行的24种可能排列中，仅打印了8行。 您可以通过将sols（）中的第二个if语句更改为“if True”来验证它是否探索了所有可能的排列，您将得到全部24个。你知道吗

要随机选择一个，只需将输入数组洗牌，然后采用第一个解决方案：

random.shuffle(arr)
print "a random ordering:", solutions(arr).next()

注意：我认为可以对算法进行调整，以便更有效地使用内存—我将对此进行研究。你知道吗

更新：这里有一个（我确信是）更有效的解决方案，它使用元组来共享内存。 在这种情况下，我实现了你的第一个排除规则。你知道吗

def sols(a,avail,avoid,x1,x2,x3):
  if not avail:
    yield None
  for i in avail:
    r = a[i]
    bad = (avoid and r[6]) or (x1 and x2 and x3 and x1 == x2 and x2 == x3 and x3 == r[11])
    if not bad:
      avail1 = avail - set([i])
      for s in sols(a, avail1, r[6], x2, x3, r[11]):
        yield (r,s)

def fromTuples(t):
  arr = []
  while isinstance(t, tuple):
    arr.append( t[0] )
    t = t[1]
  return arr

def solutions(a):
  for s in sols(a, set(range(len(a))), None, None, None, None):
    yield fromTuples(s)

def randomSolution(a):
  solutions(random.shuffle(a)).next()

其他排除规则可以通过修改sols实现，如下所示：

def sols(a, avail, x5, x6):
  ...
    bad = (x5 && abs(x5 - r[5]) < 2) and (x6 && abs(x6 - r[6]) < 2)
    ...
      for s in sols(a, avail1, r[5], r[6]):
        ...

当然，可能没有满足排除规则的任何排列，在这种情况下，您将得到StopIteration异常。你知道吗