Python 字典：将键映射到约束下的不同范围

Question

我有一本字典 d 其键是 n 整数。键不一定是连续的数字，但是，已知 d 包含 (-num_negative,0) 范围内的 num_negative 个连续键和 (0,num_positive) 范围内的 num_positive 个连续键.我想从它创建另一个字典 d2，其键是 [0, n] 范围内的连续整数，给定以下约束：

(1) 在 d 中具有来自组 num_positive 的键的元素将在 d2.

中具有相同的键

(2) d 组 num_negative 中具有负键 i 的元素将在 d2 中具有键 n+i .

一个例子:

# num_positive = 2, num_negative = 3, n=8

# num_positive group = {0,1}
# num_negative gorup = {-3,-2,-1}

d = {-6: 'h', -3: 'a', -2: 'b', -1: 'c', 0: 'd', 1: 'e', 68: 'f', 99: 'g'}
d2 = {0: 'd', 1: 'e', 2: 'g', 3: 'h', 4: 'f', 5: 'a', 6: 'b', 7: 'c'}

Answer 1

下面的代码应该可以做到。

d1={}

for key,val in d.items(): 
   if key in pos and key<=n :               #the elements that had a key from the group num_positive in d, will have the same key in d2
       d1[key] = val 
   elif key in neg and ((key+n) in range(n+1)) :             #the elements that had a negative key i from the group num_negative in d, will have the key n+i in d2
       d1[key+n] = val

#驱动程序值：

IN : n = 8
IN : pos = [0,1]
IN : neg = [-3,-2,-1]
IN : d = {-6: 'h', -3: 'a', -2: 'b', -1: 'c', 0: 'd', 1: 'e', 68: 'f', 99: 'g'} 

OUT : d1 = {5: 'a', 6: 'b', 7: 'c', 0: 'd', 1: 'e'}

注意：OP 的输出存在一些差异。其中很少有与定义不同的行为。

因此，不遵循给定约束的键将被忽略。

Answer 2

如果我理解正确，键在任一连续范围之外的项目在生成的字典中具有未定义的位置。因此，在我的解决方案中，它们使用连续范围 [0, len(d)) 中仍然空闲的任何键以任意顺序插入到生成的字典中。详情见评论。

from collections import OrderedDict

d = {-6: 'h', -3: 'a', -2: 'b', -1: 'c', 0: 'd', 1: 'e', 68: 'f', 99: 'g'}
remainder = {}

rPos = range(0, 2 + 1) # Positive consecutive range.
rNeg = range(-3, 0) # Negative consecutive range.
n = len(d)

d2 = OrderedDict([(i, None) for i in range(0, n)])

for k, v in d.items():
    if k in rNeg: # Checks if in negative consecutive range.
        d2[n + k] = v
    elif k in rPos: # Checks if in positive negative range.
        d2[k] = v
    else: # Key is outside of either range.
        remainder[k] = v

for k, v in d2.items():
    if v is None: # Finds a key still available for use.
        # Pops an arbitrary element from the remainder and inserts its
        # value into the new dict using an available key.
        d2[k] = remainder.popitem()[1]

Input: {-6: 'h', -3: 'a', -2: 'b', -1: 'c', 0: 'd', 1: 'e', 68: 'f', 99: 'g'}
Output: OrderedDict([(0, 'd'), (1, 'e'), (2, 'g'), (3, 'f'), (4, 'h'), (5, 'a'), (6, 'b'), (7, 'c')])

Python 字典：将键映射到约束下的不同范围

Python dict: mapping keys to a different range under constraints

python

language-features

dictionary