I want to use min(5,10), or Math.max(4,7). Are there functions to this effect in Ruby?
6 Answers
You can do
[5, 10].minor
[4, 7].maxThey come from the Enumerable module, so anything that includes Enumerable will have those methods available.
v2.4 introduces own Array#min and Array#max, which are way faster than Enumerable's methods because they skip calling #each.
@nicholasklick mentions another option, Enumerable#minmax, but this time returning an array of [min, max].
[4, 5, 7, 10].minmax
=> [4, 10]You can use
[5,10].min or
[4,7].maxIt's a method for Arrays.
2All those results generate garbage in a zealous attempt to handle more than two arguments. I'd be curious to see how they perform compared to good 'ol:
def max (a,b) a>b ? a : b
endwhich is, by-the-way, my official answer to your question.
3If you need to find the max/min of a hash, you can use #max_by or #min_by
people = {'joe' => 21, 'bill' => 35, 'sally' => 24}
people.min_by { |name, age| age } #=> ["joe", 21]
people.max_by { |name, age| age } #=> ["bill", 35]In addition to the provided answers, if you want to convert Enumerable#max into a max method that can call a variable number or arguments, like in some other programming languages, you could write:
def max(*values) values.max
endOutput:
max(7, 1234, 9, -78, 156)
=> 1234This abuses the properties of the splat operator to create an array object containing all the arguments provided, or an empty array object if no arguments were provided. In the latter case, the method will return nil, since calling Enumerable#max on an empty array object returns nil.
If you want to define this method on the Math module, this should do the trick:
module Math def self.max(*values) values.max end
endNote that Enumerable.max is, at least, two times slower compared to the ternary operator (?:). See Dave Morse's answer for a simpler and faster method.
def find_largest_num(nums) nums.sort[-1]
end
