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python - 如果它们没有一个接一个地去，则更改重复的列表项

问题描述

我有一个重复的整数列表。例子：

37 1 30 38 5 39 5 5 5 40 33 5 35 42 25 36 27 27 43 27

如果它们不一个接一个，我需要将重复的数字更改为其他一些数字。新号码不应与列表中的其他号码重复。例如，上面的列表应该变成这样：

37 1 30 38 5 39 8 8 8 40 33 2 35 42 25 36 27 27 43 55

这就是我得到的：

a = [37, 1, 30, 38, 5, 39, 5, 5, 5, 40, 33, 5, 35, 42, 25, 36, 27, 27, 43, 27]

duplicates = list(item for item, count in Counter(a).items() if count > 1)


for dup in duplicates:
    positions = []

    for item in range(len(a)):
        if a[item] == dup:
            positions.append(item)

    for x in range(len(positions)-1):
        if positions[x+1] - positions[x] != 1:
            ran = random.randrange(1, len(a))
            while ran in a:
                ran = random.randrange(1, len(a))
            a[positions[x+1]] = ran
        else:
            y = x
            while positions[y+1] - positions[y] == 1:
                a[positions[y+1]] = a[positions[y]]
                y += 1

[ 37、1、30、38、5、39、17、17、17、40、33、13、35、42、25、36、27、27、43、8 ] _ _ _ _ _ _ _ _ _ _ _ _ _ _

但我认为这不是一个好的解决方案。

标签： pythonpython-3.x

解决方案

您可以使用itertools.groupby以相同数字块的形式处理列表，并使用生成器表达式itertools.count来生成替换数字：

input_list = [37, 1, 30, 38, 5, 39, 5, 5, 5, 40, 33, 5, 35, 42, 25, 36, 27, 27, 43, 27]

import itertools

# make a generator that yields unused numbers
input_values = set(input_list)
unused_number = (num for num in itertools.count() if num not in input_values)

# loop over the input, grouping repeated numbers, and keeping track
# of numbers we've already seen
result = []
seen = set()
for value, group in itertools.groupby(input_list):
    # if this number has occurred already, pick a new number
    if value in seen:
        value = next(unused_number)

    # remember that we've seen this number already so future
    # occurrences will be replaced
    seen.add(value)

    # for each repeated number in this group, add the number
    # to the output one more time
    for _ in group:
        result.append(value)

print(result)
# output:
# [37, 1, 30, 38, 5, 39, 0, 0, 0, 40, 33, 2, 35, 42, 25, 36, 27, 27, 43, 3]

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