[英]Does .NET have an equivalent for Python's issubset method?
UPDATE: 更新:
As @Blender pointed out in Python set('aab').issubset(set('abb')) == True
. 正如@Blender在Python中指出的那样
set('aab').issubset(set('abb')) == True
。 For my situation this needs to return false. 对于我的情况,这需要返回false。 The number of each character needs to be taken into account.
需要考虑每个字符的数量。
Basically I have two strings and I would like to determine if one is a subset of another. 基本上,我有两个字符串,我想确定一个字符串是否为另一个字符串的子集。 Example:
例:
String A: abcd
String B: dbace
String A is a subset of string B
Characters can be in any order and there can be repeating numbers of characters. 字符可以是任意顺序,并且可以重复出现多个字符。 I had tried ordering the strings and then using String.StartsWith, but this does not work in certain situations.
我尝试过排序字符串,然后使用String.StartsWith,但这在某些情况下不起作用。 Example:
例:
String A: abcdd
string B: abbcdd
Ordering these and using StartsWith returns false because string B has two "b"s
I did some looking around and found Python's issubset method which appears to do what I want, so I'm curious if anyone has come across its equivalent in .NET (or an effective method someone has come up with on their own). 我四处张望,发现Python的issubset方法似乎可以满足我的要求,所以我很好奇是否有人遇到过.NET中的等效方法(或者有人自己提出了一种有效的方法)。
NOTE: I am looking for subsets, not anagrams. 注意:我在寻找子集,而不是字谜。
There's nothing built-in that I know of that behaves as you want it. 据我所知,没有内置函数可以像您期望的那样运行。 Strictly speaking, this isn't a real subset as it should be doing set comparisons as it is in Python (where every item in a set is unique) but it should be simple to cook one up.
严格来说,这不是真正的子集,因为它应该像Python中那样进行集合比较(集合中的每个项目都是唯一的),但是烹饪起来应该很简单。
public static bool IsSubsetOf<TSource>(this IEnumerable<TSource> lhs, IEnumerable<TSource> rhs)
{
// O(m+n)
var contents = rhs.ToList();
foreach (var item in lhs)
{
if (!contents.Remove(item))
return false;
}
return true;
}
"aab".IsSubsetOf("abb"); // false
"foo".IsSubsetOf("food"); // true
"foo".IsSubsetOf("goof"); // true
"bar".IsSubsetOf("barf"); // true
"abcd".IsSubsetOf("dbace"); // true
"abcdd".IsSubsetOf("abbcdd"); // true
If you want true set mechanics, it is just as simple. 如果您想要真正的设定机制,那就很简单。
public static bool IsTrueSubsetOf<TSource>(this IEnumerable<TSource> lhs, IEnumerable<TSource> rhs)
{
return new HashSet<TSource>(lhs).IsSubsetOf(rhs);
}
I think the best solution is to sort both of them and check the subset by Contains
method. 我认为最好的解决方案是对它们进行排序,并通过
Contains
方法检查子集。
new String(A.OrderBy(o=> o)).Contains(new String(B.OrderBy(o=>o)))
UPDATE: 更新:
new String(A.OrderBy(o=> o)
.Distinct())
.Contains(new String(B.OrderBy(o=>o)
.Distinct()))
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