In the example given below,
both the variables
hello
and
name contain different
string values:
In the case given below, we
have three strings with
the same value.
Even though the value is
same, for Ruby, these are
three different strings.
So, Ruby creates room to
have all the three strings
and
all strings take memory.
Memory is an expensive thing
when we are running programs.
We want to take as little memory
as possible.
That's where symbol comes in picture.
In this case, we
created three symbols.
However, the value is same
for all the three symbols,
so Ruby will
treat them as a single symbol.
This will take a lot less memory.
We can check if all the symbols
refer to the same thing or not
by asking each string
and each symbol what is their object_id.
Ruby assigns a unique
number to each item.
If the two items are in fact
the same item,
then they will have the
same object_id.
Even though the string values
are the same, the object_id
value is different for strings.
This means all the strings are
stored as different units.
On the other hand,
the object_id value for each
symbol is the same. It means all
these symbols are the same.