What is the difference between length, count and size?

Question

Differences with respect to array and ruby.

Answer 1

length returns the length of an array only, it dosen’t accept any additional arguments.

size is a just alias of length.

count can accept condition and count on it.

So, length or size are prefered when you just need to know the size of an array. count - when you need to count elements by some condition.

Answer 2

If you are talking of arrays, all these terms have different contextual meaning. Read on datastruct