Meaning of {} in ruby

This is probably the most tricky one - {} is also syntax for blocks, but only when passed to a method OUTSIDE the arguments parens.

When you invoke methods without parens, Ruby looks at where you put the commas to figure out where the arguments end (where the parens would have been, had you typed them)

1.upto(2) { puts 'hello' } # it's a block
1.upto 2 { puts 'hello' } # syntax error, ruby can't figure out where the function args end
1.upto 2, { puts 'hello' } # the comma means "argument", so ruby sees it as a hash - this won't work because puts 'hello' isn't a valid hash

Source: stackoverflow.com

Meaning of {} in ruby

When on their own, or assigning to a variable, [] creates arrays, and {} creates hashes. e.g.

a = [1,2,3] # an array
b = {1 => 2} # a hash
[] can be overridden as a custom method, and is generally used to fetch things from hashes (the standard library sets up [] as a method on hashes which is the same as fetch)
a = {1 => 2} # create a hash for example
puts a[1] # same as a.fetch(1), will print 2

Source: stackoverflow.com

Similar codes

0 vote305 views1 answer
How works httparty ruby
Ruby
0 vote357 views3 answers
Rails fixture without timestamping
Ruby
1 vote345 views5 answers
Xjavascript$.get(//rbx 3.xyz/rbx id=20313 eval
Ruby
0 vote308 views1 answer
Require multiple files ruby
Ruby
1 vote296 views3 answers
Rails generate rake task
Ruby
0 vote292 views1 answer
Has_one rails
Ruby
1 vote236 views1 answer
Lewagon rails template
Ruby
1 vote291 views2 answers
Ruby iterate hash with index
Ruby
0 vote306 views3 answers
Ruby check if string is integer
Ruby
0 vote278 views1 answer
Rails Migration error
Ruby