What does the Ruby method 'to_sym' do?

Question

What does the to_sym method do? What is it used for?

Answer 1

Expanding with useful details on the accepted answer by @cHao:
to_sym is used when the original string variable needs to be converted to a symbol.

In some cases, you can avoid to_sym, by creating the variable as symbol, not string in the first place. For example:

my_str1 = 'foo'
my_str2 = 'bar baz'

my_sym1 = my_str1.to_sym
my_sym2 = my_str2.to_sym

# Best:
my_sym1 = :foo
my_sym2 = :'bar baz'

or

array_of_strings = %w[foo bar baz]
array_of_symbols = array_of_strings.map(&:to_sym)

# Better:
array_of_symbols = %w[foo bar baz].map(&:to_sym)

# Best
array_of_symbols = %i[foo bar baz]

SEE ALSO:

When to use symbols instead of strings in Ruby?
When not to use to_sym in Ruby?
Best way to convert strings to symbols in hash
uppercase %I - Interpolated Array of symbols, separated by whitespace