clojure take-while
The take-while
function in Clojure is used to create a lazy sequence of elements from another sequence, as long as a given predicate function returns true for each element. It takes two arguments: the predicate function and the sequence.
Here's the syntax for using take-while
:
(take-while predicate seq)
The predicate
function is a boolean function that takes an element from the sequence and returns true or false based on some condition. The seq
argument is the sequence from which elements will be taken.
The take-while
function starts at the beginning of the sequence and takes elements as long as the predicate function returns true. Once the predicate returns false for an element, take-while
stops taking elements and returns the sequence up to that point.
Here's an example usage of take-while
:
(def numbers [1 2 3 4 5 6 7 8 9 10])
(def result (take-while #(<= % 5) numbers))
In this example, the numbers
vector contains the numbers 1 through 10. The take-while
function is used with the predicate #(<= % 5)
, which checks if a number is less than or equal to 5. The result is a lazy sequence [1 2 3 4 5]
, as take-while
stops taking elements once it encounters the number 6 which is greater than 5.
It's important to note that take-while
returns a lazy sequence, which means it doesn't actually evaluate the elements until they are needed. This can be useful for working with potentially infinite sequences, as it allows you to take elements until a certain condition is met without evaluating the entire sequence.
That's the basic usage of take-while
in Clojure. Let me know if you have any further questions.