Feb-25-2019, 01:38 PM
Dear members of python-forum,
I encounter a problem of list definition (i think). I would like to define def(S,T), where:
(i) S and T are two sets (lists in Python) and such that S is a subset of T.
(ii) def(S,T) gives the list of lists K such that S \subset K \subset T. (K is "between" S and T).
For example if S=[2] and T=[2,3,4], i want to get all the lists between [2] and [2,3,4], that is, L=[[2],[2,3],[2,4],[2,3,4]].
In the program below, i define subset(T,S) as being the elements in T which are not in S. In my example, setminus(T,S)=[3,4].
Notice that:
union(A,B) is the union of the lists A and B. (the union of sets).
interzz(A,B) is the intersection of lists A and B (the intersection of sets).
doublonsL removes the lists appearing several times in the list of lists.
The program works as follows: from the infimum S=[2] (for example) and the supremum T=[2,3,4], we compute the elements setminus(T,S) which are in T but not in S. We start from L=[[2]]. The elements 3 and 4 are in T but not in S. We take elements in L and we add lists with these elements setminus(T,S). For example:
[2]
[2],[2,3]
[2],[2,4],[2,3],[2,3,4].
My program, instead of giving what i want, gives Boolean([2],[2,3,4])=
[[2, 3, 4]]. That is, [2], [2,3] and [2,4] are missing.
I guess that my program is ugly but, actually, i just need something that works. Your suggestions would probably be helpful; thank you in advance.
Hassediagram.
I encounter a problem of list definition (i think). I would like to define def(S,T), where:
(i) S and T are two sets (lists in Python) and such that S is a subset of T.
(ii) def(S,T) gives the list of lists K such that S \subset K \subset T. (K is "between" S and T).
For example if S=[2] and T=[2,3,4], i want to get all the lists between [2] and [2,3,4], that is, L=[[2],[2,3],[2,4],[2,3,4]].
In the program below, i define subset(T,S) as being the elements in T which are not in S. In my example, setminus(T,S)=[3,4].
Notice that:
union(A,B) is the union of the lists A and B. (the union of sets).
interzz(A,B) is the intersection of lists A and B (the intersection of sets).
doublonsL removes the lists appearing several times in the list of lists.
The program works as follows: from the infimum S=[2] (for example) and the supremum T=[2,3,4], we compute the elements setminus(T,S) which are in T but not in S. We start from L=[[2]]. The elements 3 and 4 are in T but not in S. We take elements in L and we add lists with these elements setminus(T,S). For example:
[2]
[2],[2,3]
[2],[2,4],[2,3],[2,3,4].
My program, instead of giving what i want, gives Boolean([2],[2,3,4])=
[[2, 3, 4]]. That is, [2], [2,3] and [2,4] are missing.
I guess that my program is ugly but, actually, i just need something that works. Your suggestions would probably be helpful; thank you in advance.
def doublons(LM):# This def is OK. LP=[] for k in LM: if k not in LP: LP.append(k) return(LP) def doublonsL(LM): # This def is OK. LP=[] for listtt in LM: if listtt not in LP: LP.append(listtt) return(LP) def union(A,B):# This def is OK. uni=A for k in B: uni.append(k) return doublons(sorted(uni)) def interzz(lst1, lst2): # This def is OK. lst3 = [value for value in lst1 if value in lst2] return doublons(sorted(lst3)) def setminus(S,T):# This def is OK. for k in T: S.remove(k) return doublons(S) def issubset(S,T):# This def is OK. if interzz(S,T)==S: return "true" else: return "false" def Boolean(SQ,TQ): # The problem comes from this def. if issubset(SQ,TQ)=="false": # We check that S is a subset of T. print("error subset") ZED=setminus(TQ,SQ) # All the elements of TQ which are not in SQ. LILI=[SQ] MOLI=LILI[:] for k in ZED: for PPP in MOLI: LILI.append(union(PPP,[k])) LILI=MOLI[:] MOLI=LILI[:] for kj in range(0,len(LILI)): LILI[kj]=sorted(doublons(LILI[kj])) return doublonsL(LILI)Wishing you a nice week,
Hassediagram.