如何将列表中的零移动到末尾,而不是假(False)在Python中。

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英文:

How can i move just Zero to the end of my list and not False in python

问题

我的结果是 [1, 1, 2, 1, 3, 'a', False, 0, 0],我不希望False移动,我的程序将False视为0。

英文:
def move_zeros(array):
    for element in array:
        if element == 0 and type(element) is not bool:
            array.append(array.pop(array.index(element)))
    return array

print(move_zeros([False,1,0,1,2,0,1,3,"a"]))

My result is [1, 1, 2, 1, 3, 'a', False, 0, 0]
I don't want False to move, my program sees False as 0.

答案1

得分: 4

这是因为你在循环遍历列表的同时对其进行操作,以及你正确识别到的问题,即False == 00 == 0在Python中都是True。处理这个问题的一种方法是使用以下方法,使用is而不是==来检查是否等于0

def move_zeros(a):
    return [x for x in a if x is not 0] + [x for x in a if x is 0]

print(move_zeros([False,1,0,1,2,0,1,3,"a"]))

输出:

[False, 1, 1, 2, 1, 3, 'a', 0, 0]

请注意,通常情况下,使用is比较整数是不安全的,因为范围在(-5, 256)之外的整数具有不同的标识(参见此问题)。然而,在我们的情况下,我们只是使用0,所以上面的解决方案是安全的。

英文:

This is coming about because you're operating on the list while looping over it, as well as the issue that you've correctly identified, that False == 0 and 0 == 0 both are True in Python. One way to deal with this is the following, using is instead of == to check equality to 0:

def move_zeros(a):
    return [x for x in a if x is not 0] + [x for x in a if x is 0]

print(move_zeros([False,1,0,1,2,0,1,3,"a"]))

Output:

[False, 1, 1, 2, 1, 3, 'a', 0, 0]

Note that the use of is to compare integers is not safe in general because integers outside of the range (-5, 256) have different ids from each other (see this question). In our case however, we are just using 0, so the solution above is safe.

答案2

得分: 2

以下是翻译好的代码部分:

sorted(array, key=lambda x: x == 0 and type(x) is not bool)
sorted(array, key=lambda x: x == 0 and x is not False)
sorted(array, key=lambda x: 0 == x is not False)
英文:

Simple solution and showing that your check is actually ok:

>>> sorted(array, key=lambda x: x == 0 and type(x) is not bool)
[False, 1, 1, 2, 1, 3, 'a', 0, 0]

Or compare with the False singleton:

>>> sorted(array, key=lambda x: x == 0 and x is not False)
[False, 1, 1, 2, 1, 3, 'a', 0, 0]

Or if you're feeling playful, chained comparisons:

>>> sorted(array, key=lambda x: 0 == x is not False)
[False, 1, 1, 2, 1, 3, 'a', 0, 0]

答案3

得分: 1

这段代码实现了将“零”移到末尾的原地洗牌,空间复杂度为O(1),时间复杂度为O(n)。

def move_zeroes_to_end(nums):
    n = len(nums)
    non_zero = 0
    for i in range(n):
        if nums[i] != 0 or type(nums[i])==bool:
            nums[non_zero],nums[i] = nums[i],nums[non_zero]
            non_zero +=1
    return nums

l=[False,1,0,1,2,0,1,3,"a"]

print(move_zeroes_to_end(l)) #输出:[False, 1, 1, 2, 1, 3, 'a', 0, 0]
英文:

This does the inplace shuffling of "zero" to the end, costing O(1) space and O(n) time complexity.

def move_zeroes_to_end(nums):
    n = len(nums)
    non_zero = 0
    for i in range(n):
        if nums[i] != 0 or type(nums[i])==bool:
            nums[non_zero],nums[i] = nums[i],nums[non_zero]
            non_zero +=1
    return nums


l=[False,1,0,1,2,0,1,3,"a"]

print(move_zeroes_to_end(l)) #Output:[False, 1, 1, 2, 1, 3, 'a', 0, 0]

答案4

得分: 1

你可以使用pop()append()来实现这个功能,主要通过一个“自由计数”循环,通常使用while循环来完成:

def move_zeros(a):
  l = len(a)
  i = 0
  while i < l:
    if a[i] == 0:
      a.append(a.pop(i))
      l = l - 1
    else:
      i = i + 1
  return a

print(move_zeros([False, 1, 0, 1, 2, 0, 1, 3, "a"]))

生成的输出会保持原始顺序:

[False, 1, 1, 2, 1, 3, 'a', 0, 0]
英文:

You can do that with pop()+append(), just with a "free counting" loop, which is mainly a while:

def move_zeros(a):
  l=len(a)
  i=0
  while i&lt;l:
    if a[i] is 0:
      a.append(a.pop(i))
      l=l-1
    else:
      i=i+1
  return a

print(move_zeros([False,1,0,1,2,0,1,3,&quot;a&quot;]))

Produces the output maintaining the order as:

> [False, 1, 1, 2, 1, 3, 'a', 0, 0]

答案5

得分: 1

这是我的实现,使用循环和计数器:

def move_zeros(array):
    result, count = [], 0
    for i in array:
        if i == 0 and type(i) == int: count+= 1
        else: result.append(i)
    return result + [0]*count

输出

[False, 1, 1, 2, 1, 3, 'a', 0, 0]
英文:

This is my implementation, using counter with loop:

def move_zeros(array):
    result, count = [], 0
    for i in array:
        if i == 0 and type(i) == int: count+= 1
        else: result.append(i)
    return result + [0]*count

print(move_zeros([False,1,0,1,2,0,1,3,&quot;a&quot;]))

Output

[False, 1, 1, 2, 1, 3, &#39;a&#39;, 0, 0]

答案6

得分: 0

你可以将False保存为字符串。然后它不会被视为0。
将您的代码更改为:

print(move_zeros(["False", 1, 0, 1, 2, 0, 1, 3, "a"]))

英文:

You can save False as a String. Then it is not seen as 0.
change your code to:

print(move_zeros([&quot;False&quot;,1,0,1,2,0,1,3,&quot;a&quot;]))

答案7

得分: -1

将以下内容翻译为中文:

type(element) is not bool

变为:

not element == False and not element == True

它更长,但它修复了你的问题。

英文:

Change:

type(element) is not bool

to:

not element == False and not element == True

It's longer, but it fixes your problem

huangapple
  • 本文由 发表于 2020年1月6日 19:11:31
  • 转载请务必保留本文链接:https://go.coder-hub.com/59611048.html
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