如何在數字列表中找到「錯誤」

Question

對於我正在處理的項目，我必須在數字列表中找到錯誤。元素出現在具有不同值的元素後面時出錯。

# Errors are indicated by a^
l1 = [0,0,0,0,2,1,1,1,0,1,1,1,1,0,0,0] 
        ^
l2 = [2,2,1,1,1,0,0,0,0,1,0,0,3,3,2,3] 
         ^  ^

注意在l1因爲我們假設該列表就像一個圓，最後零點不是錯誤，但他們旁邊的第一個零。

我試圖實現一個遞歸函數來做到這一點，但它似乎並沒有工作。

def Checkinter(testlist1): 

    testlist = list(testlist1) 
    print(len(testlist)) 

    if len(testlist) > 2: 
     if testlist[0] not in boundaries: 
      boundaries.append(testlist[0]) 
     if testlist[0] != boundaries[-1]: 
      print('error') 
     if len(testlist) == 3 and (testlist[0] == testlist[1] == testlist[2]): 
      return None 
     if testlist[0] == testlist[-1] and len(testlist) > 3:  
      del testlist[-1] 
      Checkinter(testlist) 
     if testlist[0] != testlist[-1]: 
      del testlist[0] 
      print(testlist) 

     Checkinter(testlist) 

你知道一個有效的方法嗎？謝謝。

Answer 1

def get_errors_index(lst): 
    # Delete the right element equals to left so we avoid reporting errors 
    # due to cyclic values 
    while lst and lst[-1] == lst[0]: 
    lst.pop() 
    if not lst: 
    return [] 

    # We need to keep track of 2 indexes: 
    # - the real index, which is the index of the element in the initial 
    # iterator, used to report the erroneous indexes 
    # - the last correct index, that assumes the error did not exist 
    last_indexes, errors = {}, [] 
    correct_index = 0 

    for real_index, value in enumerate(lst): 
    last_seen_index = last_indexes.get(value) 
    if last_seen_index is not None and last_seen_index != correct_index: 
     errors.append(real_index) 
    else: 
     correct_index += 1 
     last_indexes[value] = correct_index 

    return errors 


print get_errors_index([0,0,0,0,2,1,1,1,2,1,1,1,1,0,0,0]) # [8] 
print get_errors_index([0,0,0,0,2,1,1,1,0,1,1,1,1,0,0,0]) # [8] 
print get_errors_index([0,0,0,0,2,1,1,1,1,1,1,1,0,0,0]) # [] 
print get_errors_index([0,0,0,0,2,1,1,1,1,1,1,1]) # [] 
print get_errors_index([0,0,0,0,2,1,2,1,1,2,1,1]) # [6, 9] 
print get_errors_index([0,0,0,0,2,1,2,1,1,2,1,1,0,0]) # [6, 9] 
print get_errors_index([0,0,0,0,0,0]) # []