I have two arrays list1 and list2 which have objects with some properties; userId is the Id or unique property: list1 = [ { userId: 1234, userName: 'XYZ' }, { userId: 1235, userName: 'ABC' }, ...

I'm making some comparisons with UpSetR, and I'd like to save the lists of elements that fall into each intersection. Is this possible? I can't find it anywhere... It would be pretty tedious to do ...

Are there any standard library calls I can use to either perform set operations on two arrays, or implement such logic myself (ideally as functionally and also efficiently as possible)?

I have a list of vectors as follows. data <- list(v1=c("a", "b", "c"), v2=c("g", "h", "k"), v3=c("c", "d"), v4=c...

I came across this example and I don't understand what it means. (SELECT drinker FROM Frequents) EXCEPT ALL (SELECT drinker FROM Likes); relations: Frequents(drinker, bar), Likes(drinker, beer...

I had seen this test question on Pluralsight: Given these sets: x = {'a', 'b', 'c', 'd'} y = {'c', 'e', 'f'} z = {'a', 'g', 'h', 'i'} What is the value of x | y ^ z? The expected answer is: {...

In CMake, lists are used extensively. Sometimes you have two lists of items (strings, basically), and you want to consider their intersection, difference or union. Like in this case that just came ...

Suppose we are given two 2D numpy arrays a and b with the same number of rows. Assume furthermore that we know that each row i of a and b has at most one element in common, though this element may ...

I have the following tables: work_units - self explanatory workers - self explanatory skills - every work unit requires a number of skills if you want to work on it. Every worker is proficient in...

Randomly select two sets ,both set contains distinct keys (one key may belongs to multiple sets ,one set can never contain duplicate keys ). Return a integer which represents for the number of key...

Python 2.7, numpy, create levels in the form of a list of factors. I have a data file which list independent variables, the last column indicates the class. For example: 2.34,4.23,0.001, ... ,56....

Python sets have these methods: s.union(t) s | t new set with elements from both s and t s.update(t) s |= t return set s with elements added from t Likewise, there's also these: s.intersection_up...

How do you calculate the union of two dict objects in Python, where a (key, value) pair is present in the result iff key is in either dict (unless there are duplicates)? For example, the uni...

[Update 1: As Matthew Dowle noted, I'm using data.table version 1.6.7 on R-Forge, not CRAN. You won't see the same behavior with an earlier version of data.table.] As background: I am porting some...

What's the simplest way to perform a set subtraction given two arrays in C#? Apparently this is dead easy in Ruby. Basically I just want to remove the elements from array a that are in array b: st...

I am intrigued by the following python expression: d3 = dict(d1, **d2) The task is to merge 2 dictionaries into a third one, and the above expression accomplishes the task just fine. I am intere...

I have two collections of type ICollection<MyType> called c1 and c2. I'd like to find the set of items that are in c2 that are not in c1, where the heuristic for equality is the Id property o...