Using object.Equals to compare two float[] array-elements are equal

Question

I have two float[] objects. Without writing a for-loop, I want to compare my two 1D arrays to see if they are equal numerically or not.

When I run the following code (as all elements are equal), it doesn't go through the if-statement and show the message.

How should I apply the Equals command to work properly?
Is there any compare-command I could use?

 Random r1 = new Random(1);
   int rndNumber= r1.Next(10);
   float[] m = Enumerable.Repeat((float)rndNumber, 180).ToArray();
   float[] m2 = Enumerable.Repeat((float)rndNumber, 180).ToArray();
   if (m.Equals(m2))
    {
    MessageBox.Show("we are equal");
   }

Side note: comparing floats with ==/Equals is dangerous due to nature of float computations... make sure you really need ==, not something else. — Alexei Levenkov, Nov 14 '12 at 22:16
@ Alexie: what's the dangerous side? Could you give me an example please — farzin parsa, Nov 14 '12 at 22:23
Bing result for "comparing floats..." - http://stackoverflow.com/questions/4915462/how-should-i-do-floating-point-comparison — Alexei Levenkov, Nov 14 '12 at 22:54

Servy · Accepted Answer · 2012-11-14T22:20:13.383

The Equal method for Array isn't overridden from the default object implementation that just compares the references of the objects (which aren't equal).

You want to compare the values of each element in the sequence, and ensure it has the same content in the same order. To do that, use SequenceEqual in System.Linq.Enumerable.

if(m.SequenceEqual(m2)) {...}

Internally that method will iterate through each element of each sequence and call Equals on each element pair to verify that they are all the same. While this is certainly easier (and arguably more readable) to use than a for loop, keep in mind that it will perform no better than using a for loop, it's just hiding the loop from you.

Using object.Equals to compare two float[] array-elements are equal

1 Answers1