將類變量解壓縮為列表

Question

假設我有一個“數組”

self.memory = [None] * 10000

現在讓我們說我有一個像這樣的課程：

class Process:
  def __init__(self, process_id, state, priority):
    self.process_id = process_id
    self.state = state
    self.priority = priority
  def operation_that_adds_class_variables(self):
    if self.priority > 5:
      self.urgency = 'HIGH'
    else:
      self.urgency = 'LOW'

我要對memory做一些事情，現在它具有一些值了。 我找到了第一次出現的None並且想要在其中放置一個Process 。 但是，我希望該類的實例解壓縮其初始化的self變量

def CreateProcess(process_id, state, priority):
  print 'memory before create process'
  print self.memory
  index = self.memory.index(None)
  p = Process(process_id, state, priority)
  ready_queue.append(p)
  self.memory[index] = #unpack p, with offsets in memory
  print 'memory after create process'
  print self.memory

本質上，這就是我的期望。

Memory before create process:
[1, 2, 3, 4, None, None, None, None ...]
Memory after create process
[1, 2, 3, 4, PROCESS_1, states['pending'], 3, 'HIGH URGENCY', ...]

這容易實現嗎？

Answer 1

使用切片分配：

self.memory[index:index + 4] = p.process_id, p.state, p.priority, p.urgency

注意這可以擴展self.memory ; 您可能要先進行邊界檢查：

if index <= len(self.memory) - 4:

演示：

>>> memory = [1, 2, 3, 4, None, None, None, None]
>>> index = memory.index(None)
>>> memory[index:index + 4] = 'foo', 'bar', 'spam', 'eggs'
>>> memory
[1, 2, 3, 4, 'foo', 'bar', 'spam', 'eggs']

為了支持可變數量的屬性，可以擴展Process類以跟蹤需要包括哪些屬性：

class Process:
    urgency = None

    def __init__(self, process_id, state, priority):
        self.process_id = process_id
        self.state = state
        self.priority = priority

    def operation_that_adds_class_variables(self):
        if self.priority > 5:
            self.urgency = 'HIGH'
        else:
            self.urgency = 'LOW'

    @property
    def memory_values(self):
        res = (self.process_id, self.state, self.priority)
        if self.urgency is not None:
            return res + (self.urgency,)
        return res

然后將其結果存儲在您的“內存”中：

proc_memory = p.memory_values
if index <= len(self.memory) - len(proc_memory):
    self.memory[index:index + len(proc_memory)] = proc_memory

您不能隨意列出屬性，因為擁有屬性的實例__dict__對象是一個字典。 它沒有命令。 您必須自己指定一個訂單。