c# - filtering a list using LINQ -

i have list of project objects:

ienumerable<project> projects 

a project class property called tags. int[]

i have variable called filteredtags int[].

so lets filtered tags variable looks this:

 int[] filteredtags = new int[]{1, 3}; 

i want filter list (projects) return projects have of tags listed in filter (in case @ least tag 1 , tag 3 in tags property).

i trying use where() , contains() seems work if comparing against single value. how compare list against list need match on items in filtered list ??

edit: better yet, that:

var filteredprojects =      projects.where(p => filteredtags.all(tag => p.tags.contains(tag))); 

edit2: honestly, don't know 1 better, if performance not critical, choose 1 think more readable. if is, you'll have benchmark somehow.

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probably intersect way go:

void main() {     var projects = new list<project>();     projects.add(new project { name = "project1", tags = new int[] { 2, 5, 3, 1 } });     projects.add(new project { name = "project2", tags = new int[] { 1, 4, 7 } });     projects.add(new project { name = "project3", tags = new int[] { 1, 7, 12, 3 } });      var filteredtags = new int []{ 1, 3 };     var filteredprojects = projects.where(p => p.tags.intersect(filteredtags).count() == filteredtags.length);   }   class project {     public string name;     public int[] tags; } 

although seems little ugly @ first. may first apply distinct filteredtags if aren't sure whether unique in list, otherwise counts comparison won't work expected.