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In Ruby, is there any difference between the functionalities of each, map, and collect?
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There's no difference, in fact map is implemented in C as rb_ary_collect and enum_collect (eg. there is a difference between map on an array and on any other enum, but no difference between map and collect ). Why do both map and collect exist in Ruby? The map function has many naming conventions in different languages.
The main difference between map and forEach is that the map method returns a new array by applying the callback function on each element of an array, while the forEach method doesn't return anything. You can use the forEach method to mutate the source array, but this isn't really the way it's meant to be used.
The collect() of enumerable is an inbuilt method in Ruby returns a new array with the results of running block once for every element in enum. The object is repeated every time for each enum. In case no object is given, it return nil for each enum.
The map() of enumerable is an inbuilt method in Ruby returns a new array with the results of running block once for every element in enum. The object is repeated every time for each enum. In case no object is given, it return nil for each enum.
Each will evaluate the block but throws away the result of Each block's evaluation and returns the original array.
irb(main):> [1,2,3].each {|x| x*2} => [1, 2, 3] Map/collect return an array constructed as the result of calling the block for each item in the array.
irb(main):> [1,2,3].collect {|x| x*2} => [2, 4, 6] each is different from map and collect, but map and collect are the same (technically map is an alias for collect, but in my experience map is used a lot more frequently).
each performs the enclosed block for each element in the (Enumerable) receiver:
[1,2,3,4].each {|n| puts n*2} # Outputs: # 2 # 4 # 6 # 8 map and collect produce a new Array containing the results of the block applied to each element of the receiver:
[1,2,3,4].map {|n| n*2} # => [2,4,6,8] There's also map! / collect! defined on Arrays; they modify the receiver in place:
a = [1,2,3,4] a.map {|n| n*2} # => [2,4,6,8] puts a.inspect # prints: "[1,2,3,4]" a.map! {|n| n+1} puts a.inspect # prints: "[2,3,4,5]" If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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