如何用现有词典填充书架

Question

假设我有一本数百兆字节的大字典，我想将其放入磁盘架中。我正在使用 pypar 来利用 MPI 生成主列表的清理位。实现这一目标的最佳方法是什么？例子：

# much earlier
masterDict = shelve.open( 'aShelveFile' )
# .. . . . . 
# then we work out which parts of masterDict to keep
# and we put into aCleanDict
# then use mpi pypar to send the cleaned bits to the master rank
if pypar.rank() == 0:
  tempdict = {}
  for p in range(1,pypar.size()):
    tempdict.append(pypar.receive(p))
  for l1 in tempdict:
    for l2 in l1:
      realDict.append(l2)
  for p in range(1,pypar.size()):
    pypar.send(realDict,p)

  # now realDict has all the cleaned bits
  # which we send to the other hosts
else:
  pypar.send(aCleanDict, 0 )
  aCleanDict = pypar.receive( 0 )

# now to replace masterDict  with aCleanDict
# note: cannot send shelve dictonaries using pypar

# insert stackover flow code here.

Answer 1

在这里，您搁置了一个简单的字典，并通过键 myDict 使其可访问：

import shelve
myDict = {"a" : 1, "b" : 2}
myShelvedDict = shelve.open("my_shelved_dictionary.db")
myShelvedDict["myDict"] = myDict

请注意，字典的内容必须是可pickle的，就像要搁置的任何内容一样。

如果您想复制架子中字典的结构，即没有 myDict 键，而是将字典的键直接作为架子的键，则可以使用 update shelve 方法：

myShelvedDict.update(myDict)

shelve 接口与 dict 接口有很大的重叠。