Terrible test suite. The test suite fails if you don't replace every removed entry with exactly one space.

The pass criteria should not be specific to the number of spaces that are left instead of the omitted state names. This beats the purpose of the exercise. There should either be no extra spaces left in the solutions, or it should not be specific to how the author of the challenge solved the problem.

I've never cared so much about America

Inconsistent behavior - if you are going to make a question like this, make it representative of what would actual be done and not some arbitrary undocumented rules like "replace a two-word state name with a space"

I am a new Matlab programmer and don't know much about regexp. Is it not good to use that?

@Apurbo, regexp is a great function for its intended application. Unfortunately, some Cody users have exploited that function, and a few others, to cheat—the comment in this solution is referring to that widespread problem.

did not give the list of states names

Something wrong in test 1