Sams Teach Yourself Ruby in 21 Days

Name Tags, Not Suitcases

If you're new to programming, or you're used to a reference-oriented language like Java, this part will make all the sense in the world. It might be a problem if you're more used to C or C++.

As mentioned in Day 1, an equals sign (=) accomplishes reference, or assignment; in other words, it gives an object a name. But the name does not in any way contain the object. By way of illustration, let's use irb to make a String object and give it a simple name:

irb(main):01:0> a
						=
						"zif"
"zif"

What does it mean to assign b to a?

irb(main):02:0> b
						=
						a
"zif"

The correct way to think of this is that the string now has two names, a and b. It has not become two strings; no copy has been generated. We can try to alter a and b separately ...