Difference between double equals and triple equals for String Comparison in Elixir

Question

I was reading a book on Elixir: Introducing Elixir.

On string compare it says that:

Elixir offers two options for comparing string equality, == and === operators. The == operator is generally the simplest though the other produces the same result.

Whats the purpose of having two operators if they mean the same thing?

Answer 1

One example that comes to mind is floats - which use the same comparison functions as strings:

iex> 1 == 1    #true iex> 1 == 1.0  #true iex> 1 === 1   #true iex> 1 === 1.0 #false 

And for !==

iex> 1 != 2    #true iex> 1 != 1.0  #false iex> 1 !== 2   #true iex> 1 !== 1.0 #true 

It is worth noting that these functions use the following Erlang expressions:

Elixir | Erlang ==     | == ===    | =:= !=     | /= !==    | =/= 

From the Erlang documentation:

When comparing an integer to a float, the term with the lesser precision is converted into the type of the other term, unless the operator is one of =:= or =/=. A float is more precise than an integer until all significant figures of the float are to the left of the decimal point. This happens when the float is larger/smaller than +/-9007199254740992.0. The conversion strategy is changed depending on the size of the float because otherwise comparison of large floats and integers would lose their transitivity.