Is there a straightforward way to do something like the following without excessive looping?
myArray = [["a","b"],["c","d"],["e","f"]]
if myArray.includes?("c")
...
I know this works fine if it's just a normal array of chars... but I would like something equally as elegant for an array of an array of chars (bonus points for helping convert this to an array of tuples).
If you only need a true/false answer you can flatten the array and call include on that:
>> myArray.flatten.include?("c")
=> true
myArray.flatten.index("c").
index returns the position of "c" in the array (or nil if "c" isn't found), whereas include? only returns true or false.You can use assoc:
my_array = [['a', 'b'], ['c', 'd'], ['e', 'f']]
if my_array.assoc('c')
# ...
It actually returns the whole subarray:
my_array.assoc('c') #=> ["c", "d"]
or nil if there is no match:
my_array.assoc('g') #=> nil
There's also rassoc to search for the second element:
my_array.rassoc('d') #=> ["c", "d"]
my_array = [["a","b"],["c","d"],["e","f"]]
p my_hash = my_array.to_h # => {"a"=>"b", "c"=>"d", "e"=>"f"}
p my_hash.key?("c") # => true
You can use Array#any?
myArray = [["a","b"],["c","d"],["e","f"]]
if myArray.any? { |x| x.includes?("c") }
# some code here
The find_index method works well for this:
myArray = [["a","b"],["c","d"],["e","f"]]
puts "found!" if myArray.find_index {|a| a[0] == "c" }
The return value is the array index of the pair or nil if the pair is not found.
You can capture the pair's value (or nil if not found) this way:
myArray.find_index {|a| a[0] == "c" } || [nil, nil])[1]
# => "d"
myArrayare of the same size, you could write,require 'array'; m = Matrix[*myArray]; m.index("f") #=> [2,1]; m.index("g") #=> nil,[2,1]being truthy.myArraywould generally be writtenmy_array. Snake-case is lower-case letters and underscores, and in the case of method names, the last character can be"?"or"!". You don't have to adopt that convention, but 99%+ of Rubiests do.