Python - 删除多维数组中的项目答案

【问题标题】：Python - removing items in multidimensional arrayPython - 删除多维数组中的项目
【发布时间】：2017-05-11 23:33:28
【问题描述】：

我有一个像这样的多维数组：

[["asdf","bmnl", "123","456,"0","999","1234","3456"],["qwer","tyui","789","657,"122","9","673","1"]]

但是，在多维数组中，每个数组只需要最后6项，不需要前两项。如何从多维数组中的每个数组中删除前两条数据，使其看起来像：

[["123","456,"0","999","1234","3456"],["789","657,"122","9","673","1"]]

到目前为止，我已经这样做了：

list1 = []
list2 = []
for row in rows:
    list1.append(row[0].split(',')) #to put the split list into the top i i.e. [["asdf","bmnl", "123","456,"0","999","1234","3456"]["qwer","tyui","789","657,"122","9","673","1"]]
for i in list1:
    for index in len(list1):
        if index >=2:
             list2.append(index) #this does not work and causes errors

我该如何解决这个问题，所以输出将是：

[["123","456,"0","999","1234","3456"],["789","657,"122","9","673","1"]]

谢谢

【问题讨论】：

标签： python arrays multidimensional-array append

【解决方案1】：

您可以使用list comprehension，如下所示：

[item[2:] for item in my_list]

item[2:] 称为列表切片，意思是对于my_list 的每个子列表，我们从索引2 中取出items 直到最后一项。

输出：

>>> my_list = [["asdf", "bmnl", "123", "456", "0", "999", "1234", "3456"], ["qwer", "tyui", "789", "657", "122", "9", "673", "1"]]
>>>
>>> [item[2:] for item in my_list]
[['123', '456', '0', '999', '1234', '3456'], ['789', '657', '122', '9', '673', '1']]

【讨论】：

【解决方案2】：

这是list comprehension 的典型用例：

list2 = [item[2:] for item in list1]

【讨论】：

【解决方案3】：

只需使用列表推导式并从索引 2 中获取每个子列表中的每个元素：

>>> array = [["asdf","bmnl", "123","456","0","999","1234","3456"],["qwer","tyui","789","657","122","9","673","1"]]
>>> [sublist[2:] for sublist in array]
[['123', '456', '0', '999', '1234', '3456'], ['789', '657', '122', '9', '673', '1']]

【讨论】：

【解决方案4】：

start = [["asdf","bmnl", "123","456","0","999","1234","3456"],
         ["qwer","tyui","789","657","122","9","673","1"]]

list_1, list_2 = [i[2:] for i in start] # I use list comprehension to create a multidimensional 
                                        # list that contains slices of each object in the base 
                                        # list and unwrap it to list_1 and list_2

同

n_list = [] #create an empty new list
for i in start: #loop through the origional
    n_list.append(i[2:]) #append slices of each item to the new list
list_1, list_2 = n_list #unwrap the list

【讨论】：

请在代码中包含一些解释，以便其他人可以理解它是如何工作的

【解决方案5】：

lst = [["asdf","bmnl", "123","456","0","999","1234","3456"],["qwer","tyui","789","657","122","9","673","1"]]
for i in lst:
    del i[0:2] #deleting 0 and 1 index from each list

print lst

【讨论】：