The pushfirst! method is used to add an element at the beginning of the CircularDeque object.
Note:CircularDequeis a double-ended queue implementation using a circular buffer of fixed capacity (while creating the deque, the capacity should be provided). It supports insertion and deletion on both ends.
pushfirst!(deque_object, items...) -> collection
This method takes an CircularDeque object and the values to be inserted as arguments.
This method returns the CircularDeque object, which is passed in the arguments.
using DataStructures#create a new CircularDeque object for 5 elementsdeque = CircularDeque{Int}(5);push!(deque,2);push!(deque, 3);push!(deque, 4);println("\nDeque -> $(deque)")# insert 0 and 1 at the beginning of the dequepushfirst!(deque, 0, 1);println("\nDeque -> $(deque)")
CircularDeque object with the name deque. For this object, we set the capacity as 5, meaning it can hold 5 elements. Also, we set the elements of deque to be an integer datatype.2,3, and 4, to deque using the push! method.pushfirst! method to add two elements, 0,1, at the beginning of the deque object. After calling this method, the elements of deque will be 0,1,2,3,4 .