在循环过程中执行过程

Question

我的代码基本上像这样

P = matrix # initialise value of P matrix
x = some other matrix
for i, val in enumerate(vals):
    lots of matrix calculations involving P and x
    y = z - j # this is the important line
    lots of matrix calculations UPDATING P and x
    return values of P and x for each step

现在，我想更改代码，以便如果y大于某个阈值，例如y> 0.5，我将p和x重置为它们的初始值 - 然后再次继续循环，就好像它只是从头开始启动一样。我不确定最好的方法，我是Python的新手在功能中。

欢呼

s

Answer 1

python list中是一个可变的对象。要在计算中间从头开始，请使用原始值保持原始列表和重新分配P和X的深度副本，然后继续。这样的东西：

import copy
P = matrix # initialise value of P matrix
x = some other matrix
p1= copy.deepcopy(P)
x1= copy.deepcopy(x)
for i, val in enumerate(vals):
  lots of matrix calculations involving P and x
  y = z - j # this is the important line
  if y > threshold:
    P = p1
    x = x1
    continue
  lots of matrix calculations UPDATING P and x
  return values of P and x for each step