How do filter and reduce work in different programming languages?

Can you explain how the filter and reduce functions work in Python?

In Python, the filter function creates an iterator from elements of an iterable for which a function returns true. The reduce function, from the functools module, applies a rolling computation to sequential pairs of values in a list.

What about in JavaScript?

In JavaScript, filter creates a new array with all elements that pass the test implemented by the provided function. reduce executes a reducer function on each element of the array, resulting in a single output value.

How is it implemented in Java?

In Java, you can use the Stream API. The filter method returns a stream consisting of the elements that match the given predicate, while reduce performs a reduction on the elements of the stream using an associative accumulation function.

Can you give an example in Ruby?

Sure! In Ruby, select is used for filtering, and reduce (or inject) is used for reducing. For example, array.select { |x| x.even? } filters even numbers, and array.reduce(:+) sums up all elements.