What is the difference between symbol and string ?

Here is an explanation of the difference between symbols and strings in Ruby on Rails:

Symbols vs Strings

In Ruby, both symbols and strings are used to represent text, but they have some key differences:

Memory Usage

• Strings are mutable and can be modified after creation. Each string takes up a unique block of memory.
• Symbols are immutable and always have the same object ID. Ruby only stores one copy of each symbol in memory.

Equality

• Two strings are only equal if they have the same characters, even if they look the same.
• Two symbols are only equal if they have the same name, even if they look differ...