Python-通过嵌套循环循环打印项目（如果项目发生更改）

我正在循环几个嵌套的循环。如果第一个循环的项目发生变化，我想打印它。我该怎么做

for slope in slopeList:
    for yarddist in yardDistList:
                      for chiptreesperacre in chipAcreList:
                          for chipvolpertree in chipVolList:
                              for smalllognumber in smallAcreList:
                                   for smalltreevolpertree in smallVolList:
                                       for largelogperacre in largeAcreList:
                                           for largetreevolpertree in largeVolList:
                                               data = [slope, yarddist, chiptreesperacre, chipvolpertree, smalllognumber, smalltreevolpertree, largelogperacre, largetreevolpertree]
                                               if slope changes:
                                                   print data

---

存储以前看到的值，并进行比较：

previous_slope = None
for slope in as_many_loops_as_you_like:
    data = [slope, other_stuff]
    if slope != previous_slope:
        print data
        previous_slope = slope

---

可以将上一个_坡度添加到a，并在内部循环中添加后观察其长度：

slope = set()
slope.add(previous_slope)
old_length = len(slope)
for first_loop:
   slope.add(current_slope)
   if len(slope) > old_length: 
     print 'Changed!'
     break

---

对每个内部循环重复此模式。

您认为“it更改”是什么意思？它与上一次迭代中的值不同？循环中循环中循环中循环中循环中循环中循环中循环中循环系列？你还有什么建议？