In the context of unit testing some functions, I’m trying to establish the equality of 2 DataFrames using python pandas: ipdb> expect 1 2 2012-01-01 00:00:00+00:00 NaN 3 2013-05-14 12:00:00+00:00 3 NaN ipdb> df identifier 1 2 timestamp 2012-01-01 00:00:00+00:00 NaN 3 2013-05-14 12:00:00+00:00 3 NaN ipdb> df[1][0] nan ipdb> df[1][0], expect[1][0] (nan, nan) ipdb> … Read more
How do I check if two objects, e.g. dataframes, are value equal in R? By value equal, I mean the value of each row of each column of one dataframe is equal to the value of the corresponding row and column in the second dataframe. Answer It is not clear what it means to test … Read more
Can someone please explain to me why the output from the following code is saying that arrays are not equal? int main() { int iar1[] = {1,2,3,4,5}; int iar2[] = {1,2,3,4,5}; if (iar1 == iar2) cout << “Arrays are equal.”; else cout << “Arrays are not equal.”; return 0; } Answer if (iar1 == iar2) … Read more
Say we have 5 string arrays as such: string[] a = {“The”,”Big”, “Ant”}; string[] b = {“Big”,”Ant”,”Ran”}; string[] c = {“The”,”Big”,”Ant”}; string[] d = {“No”,”Ants”,”Here”}; string[] e = {“The”, “Big”, “Ant”, “Ran”, “Too”, “Far”}; Is there a method to compare these strings to each other without looping through them in C# such that only a … Read more
If I have two objects o1 and o2, and we know that id(o1) == id(o2) returns true. Then, does it follow that o1 == o2 Or is this not always the case? The paper I’m working on says this is not the case, but in my opinion it should be true! Answer Not always: >>> … Read more
A discussion came up at work recently about Sets, which in Scala support the zip method and how this can lead to bugs, e.g. scala> val words = Set(“one”, “two”, “three”) scala> words zip (words map (_.length)) res1: Set[(java.lang.String, Int)] = Set((one,3), (two,5)) I think it’s pretty clear that Sets shouldn’t support a zip operation, … Read more
First example: int main(){ using namespace std; vector<int> v1{10, 20, 30, 40, 50}; vector<int> v2{10, 20, 30, 40, 50}; if(v1==v2) cout<<“equal”; else cout<<“unequal”; } // it returns equal Second example: int main(){ using namespace std; vector<int> v1{10, 20, 30, 40, 50}; vector<int> v2{10, 20, 100000, 40, 50}; if(v1==v2) cout<<“equal”; else cout<<“unequal”; } // it returns … Read more
In Ruby 1.9.2 on Rails 3.0.3, I’m attempting to test for object equality between two Friend (class inherits from ActiveRecord::Base) objects. The objects are equal, but the test fails: Failure/Error: Friend.new(name: ‘Bob’).should eql(Friend.new(name: ‘Bob’)) expected #<Friend id: nil, event_id: nil, name: ‘Bob’, created_at: nil, updated_at: nil> got #<Friend id: nil, event_id: nil, name: ‘Bob’, created_at: … Read more
I’ve noticed these two interfaces, and several associated classes, have been added in .NET 4. They seem a bit superfluous to me; I’ve read several blogs about them, but I still can’t figure out what problem they solve that was tricky before .NET 4. What use are IStructuralEquatable and IStructuralComparable? Answer All types in .NET … Read more
Other than stepping through the elements one by one, how do I compare two lists of strings for equality (in .NET 3.0): This fails: // Expected result. List<string> expected = new List<string>(); expected.Add( “a” ); expected.Add( “b” ); expected.Add( “c” ); // Actual result actual = new List<string>(); actual.Add( “a” ); actual.Add( “b” ); actual.Add( … Read more
