Python Tulpe Key for Dict Partial Lookup [英] Python Tulpe Key For Dict Partial Lookup

问题描述

我有一个包含5个值的元组作为键的字典。例如：

D [i，j，k，g，h] = value。

需要使用某个部分密钥对（i1，g1）处理所有元素：

我现在需要每一对（i1，g1）所有的值为i == i1和g == g1在完整的键。

什么是pythonic和有效的方式来检索这个，知道我需要所有对的元素和每个完整的键属于正好一个部分键？

是否比字典更合适的数据结构？

一个参考实现是这样的：

  results = {} $ b中的i 
对于G中的g 
结果[i，g] = [] 
 
对于i，j，k，g，h在D ：
如果i1 == i和g1 == g：
结果[i，g] .append（D [i，j，k，g，h]）
  

解决方案

假设你知道不同索引的所有有效值，你可以得到所有可能 c code code
$ b

  import itertools 
 I = [3,6,9] 
 J =范围（10）
 K =abcde
 G = [first，second] 
 H = range（10,20）
 
 for tup in itertools.product（I，J，K，G，H）：
 my_dict [tup] = 0 
  

限制生成的索引只对一个/几个生成的索引进行限制，例如所有的键， i = 6 将是：

  itertools.product（（6， ） J，K，G，H）
  

一个函数让你指定你想要所有的索引，其中 i == 6和g ==first将如下所示：

  def partial_indices（i_vals = I，j_vals = J，k_vals = K，g_vals = G，h_vals = H）：
返回itertools.product（i_vals，j_vals，k_vals，g_vals，h_vals）
 
 partial_indices（i_vals =（6，），g_vals =（first））
  

或者假设并非所有这些都存在于字典中，您也可以通过字典作为参数，并在生成密钥之前检查会员资格：

  def items_with_partial_indices（d，i_vals = I，j_vals = J，k_vals = K，g_vals = G，h_vals = H）：
 for tup in itertools.product（i_vals，j_vals，k_vals，g_vals，h_vals ）：
 try：
 yield tup，d [tup] 
除了KeyError：
 pass 
  




I have a dictionary with a tuple of 5 values as a key. For example:

D[i,j,k,g,h] = value.

Now i need to process all elements with a certain partial key pair (i1,g1):

I need now for each pair (i1,g1) all values that have i == i1 and g == g1 in the full key.

What is an pythonic and efficient way to retrieve this, knowing that i need the elements for all pairs and each full key belongs to exactly one partial key?

Is there a more appropriate data structure than dictionaries?

One reference implementation is this:

    results = {}
    for i in I:
        for g in G:
            results[i,g] = []

    for i,j,k,g,h in D:
        if i1 == i and g1 == g:
            results[i,g].append(D[i,j,k,g,h])

解决方案

Assuming you know all the valid values for the different indices you can get all possible keys using itertools.product:

import itertools
I = [3,6,9]
J = range(10)
K = "abcde"
G = ["first","second"]
H = range(10,20)

for tup in itertools.product(I,J,K,G,H):
    my_dict[tup] = 0

To restrict the indices generated just put a limit on one / several of the indices that gets generated, for instance all of the keys where i = 6 would be:

itertools.product((6,), J,K,G,H)

A function to let you specify you want all the indices where i==6 and g =="first" would look like this:

def partial_indices(i_vals=I, j_vals=J, k_vals=K, g_vals = G, h_vals = H):
    return itertools.product(i_vals, j_vals, k_vals, g_vals, h_vals)

partial_indices(i_vals=(6,), g_vals=("first",))

Or assuming that not all of these are present in the dictionary you can also pass the dictionary as an argument and check for membership before generating the keys:

def items_with_partial_indices(d, i_vals=I, j_vals=J, k_vals=K, g_vals = G, h_vals = H):
    for tup in itertools.product(i_vals, j_vals, k_vals, g_vals, h_vals):
        try:
            yield tup, d[tup]
        except KeyError:
            pass

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