Symbols Notes Day 1

Question 1

what is a symbol?

Answer 1

a symbol is a data type similar to strings

Question 2

what is the difference between a symbol and a string?

Answer 2

The most apparent difference between strings and symbols is that strings are mutable, while symbols are immutable

Question 3

how do you denote a symbol?

Answer 3

using a colon
sym = :hello
sym[0] = “x”
p sym # => :hello

Question 4

what is object_id and how do you find it?

Answer 4

object_id method. This will return the memory address of some data

Question 5

why are symbols useful?

Answer 5

If we don't intend to mutate the string, we can use a symbol to save some memory. A symbol value will be stored in exactly one memory location:
"hello".object_id   # => 70233443667980
"hello".object_id   # => 70233443606440
\:hello.object_id    # => 2899228
\:hello.object_id    # => 2899228

Question 6

how do you use symbols as hash keys?

Answer 6

When initializing a hash with symbol keys, Ruby offers a shortcut. We can drop the rocket (=>) and move the colon (:) to the right of the symbol:

my_bootcamp = { name:”App Academy”, color:”red”, locations:[“NY”, “SF”, “ONLINE”] }
p my_bootcamp # => {:name=>”App Academy”, :color=>”red”, :locations=>[“NY”, “SF”, “ONLINE”]}
p my_bootcamp[:color] #=> “red