Ruby Array Find Vs Select

Hammerhead find executes the block you provide for each element in the array.

Ruby array find vs select.

Array filled with only those original items where the block you gave it returned true. Map returns a new array filled with whatever gets returned by the block each time it runs. The select method works in a similar way but it constructs a new array containing all of the elements that match. Select iterates over each item in the enumerable collects all the items matching the condition passed and those are returned.

The class must provide a method each which yields successive members of the collection. Returns a new array. Select is a array class method which returns a new array containing all elements of array for which the given block returns a true value. If it doesn t find anything after iterating through all of the elements it returns nil.

In the first form if no arguments are sent the new array will be empty. Without select that looks like this. When a size and an optional default are sent an array is created with size copies of default take notice that all elements will reference the same object default. Removes all the nil values from the array.

Example for count method. Even numbers 1 2 3 4 5 6 each do n. A new array containing all elements of array for which the given block returns a true value. Arrays in ruby inherit from enumerable so running find all or select on an array in ruby will yield the same result.

For example you can find all the even numbers in a list. The enumerable mixin provides collection classes with several traversal and searching methods and with the ability to sort. Let s consider the same example as above. Array 2 4 34 65 754 72456 and we want to find elements greater than 100.

Thus select returns an array. Each with index passes not just the current item but whatever position in the array it was located in. Obj specific element to found return. Select requires a condition to be passed for evaluation.

It can also find the total number of a particular element in the array. Count is a array class method which returns the number of elements in the array. You can use the select method in ruby to filter an array of objects. If max min or sort is used the objects in the collection must also implement a meaningful operator as these methods rely on an ordering between members of the collection.

If the last expression in the block evaluates to true the find method returns the value and stops iterating.