从数字列表生成“高效”的编码

Question

我在想这个问题。假设你有一组数字列表：

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19, 21, 22, 23, 999, 1000, 1001

有没有任何库或代码片段可以将以下内容转换成类似于以下的形式：

1-13, 19, 21-23, 999-1001

换句话说，将一个完整的数字列表缩减为一堆范围。我找不到相关内容。如果不存在这样的东西，有没有人对高效实现有一些想法？

- cb22

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相关链接: 如何将数组中的数字序列转换为数字范围 （但使用 JavaScript） - Cody Gray

Answer 1

def get_groups(lst):
    slices = [i+1 for i, v in enumerate(zip(lst, l[1:])) if v[0] != v[1]-1] 
    slices = [0] + slices + [len(lst)]
    for start, end in zip(slices, slices[1:]):
        yield lst[start:end]

>>> list(get_groups([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19, 21, 22, 23, 999, 1000, 1001]))
[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], [19], [21, 22, 23], [999, 1000, 1001]]

或者

def get_ranges(lst):
    slices = [i+1 for i, v in enumerate(zip(lst, l[1:])) if v[0] != v[1]-1]
    slices = [0] + slices + [len(lst)]
    for start, end in zip(slices, slices[1:]):
        yield "%d-%d" % (lst[start], lst[end-1])

>>> list(get_ranges([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19, 21, 22, 23, 999, 1000, 1001]))
['1-13', '19-19', '21-23', '999-1001']

- Andrew Clark

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+1 for 生成器和最快的（最坏情况下，至少）： Steven - 0.954934120178 inspectorG4dget - 1.70556592941 Andrew - 0.000923871994019这是在一个随机1000个整数列表的1000次迭代中得出的结果。 - cb22

Answer 2

def compress(nums):
    nums = [int(i) for i in nums.strip().split(',')]
    answer = []
    start = nums[0]
    prev = nums[0]
    for num in nums:
        if num-prev != 1:
            answer.append("%d-%d" %(start, prev))
            start = num
        prev = num
    answer.append("%d-%d" %(start, prev))
    return answer[1:]

>>> compress("1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19, 21, 22, 23, 999, 1000, 1001")
['1-13', '19-19', '21-23', '999-1001']

希望这能有所帮助

- inspectorG4dget

Answer 3

l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19, 21, 22, 23, 999, 1000, 1001]
range_pos = []
start=0
end=0
for i in range(1,len(l)):
    if l[i] - l[i-1] == 1:
        end = i
    else:
        range_pos.append((start, end))
        start = end = i
range_pos.append((start, end))
ranges = ["%s-%s" % (l[s], l[e]) if s < e else str(l[s]) for (s, e) in range_pos]
print ', '.join(ranges)

给予：

1-13, 19, 21-23, 999-1001

- Steven Rumbalski