0
def a(p): return p + 1
def b(p): return p + 2
def c(p): return p + 3
l= [a,b,c]
import itertools
ll = itertools.combinations(l, 2)
[x for x in ll]
[(<function a at 0x00CBD770>, <function b at 0x00CBD7F0>),
(<function a at 0x00CBD770>, <function c at 0x00BB27F0>),
(<function b at 0x00CBD7F0>, <function c at 0x00BB27F0>)]
Q1:這裏,如何在簡單的線條(S)返回一個lambda列表:分配一個可檢索的唯一ID到Python中更改的lambda列表?
[a(b(1)), # not the result of a(b(1)), but just a lambda object
a(c(1)), # also items may more than 2 here if itertools.combinations(l, 4)
b(c(1))]
Q2:
假設我定義的另一個功能d
def d(p): return p + 4
l= [a,b,c,d]
ll = itertools.combinations(l, 2)
[(<function a at 0x00CBD770>, <function b at 0x00CBD7F0>),
(<function a at 0x00CBD770>, <function c at 0x00BB27F0>),
(<function a at 0x00CBD770>, <function d at 0x00CBDC70>),
(<function b at 0x00CBD7F0>, <function c at 0x00BB27F0>),
(<function b at 0x00CBD7F0>, <function d at 0x00CBDC70>),
(<function c at 0x00BB27F0>, <function d at 0x00CBDC70>)]
這個組合與不同的序列比較與最後一個:
ab,ac,ad,bc,bd,cd
=================
ab,ac,bc
但我希望將所有可能的項目有unque ID,這意味着不管如何
l= [a,b,c,d]
或
l= [b,a,c,d]
PR
l= [a,b,e,d]
取「ac」 for ex充足:「ac」和其他可能的項目始終與唯一的ID綁定,然後我可以訪問「ac」與該唯一的ID。我想這就像爲每個項目創建一個可擴展的哈希表。
那麼,是否可以給lambda項分配一個int ID或「HASH」?我也希望這種映射關係應該能夠作爲文件存儲在磁盤中,並且可以在以後檢索。
謝謝你的任何想法。
樣本解釋Q2
=====================
l= [a,b,c,d]
func_combos = itertools.combinations(l, 2)
compositions = [compose(f1, f2) for f1, f2 in func_combos]
[compositions[x](100) for x in compositions] # take very long time to finish
[result1,
result2,
result3,
...
]
======== three days later on another machine ======
l= [a,c,b,e,f,g,h]
[compositions[x](100) for x in compositions] # take very long time to finish
[newresult1,
newresult2,
newresult3,
...
]
but wait: here we can saving time: take "ac" for example:
[result1, tag
result2, tag_for_ac_aka_uniqueID_or_hash
result3, tag
...
]
we just need to check if the "ac" tag exists we can reduce the calculation:
if hash_of(ac) in list(result.taglist):
copy result to new result:
當你開始談論哈希時,我不清楚你想要什麼。你能給出一個例子,說明你想要一個給定函數的唯一ID嗎? – aaronasterling 2010-11-24 06:54:21
問題已更新,謝謝 – user478514 2010-11-24 07:29:35