Pop it or Shift it 🤔 ?

Recently i started looking into Data Structures and algorithms, and so far i'm loving it, however, sometimes it can be challenging.

Some days it has made me contemplate about becoming a fisherman, but i find ways to stay motivated and keep on pushing myself to learn it consistently.

as you know, data structures and algorithms mainly focuses on perfomance and it was only a matter of time until i run into one of the most common array dilemmas (if you care about perfomance), pop vs shift.

so i did some research and found out the following.

i'll lay out some examples of both pop and shift.

unshift

adds a new item at the beginning of an array.

const cars = ['Toyota', 'Hyundai', 'Mazda'];

cars.unshift('Bmw', 'Mercedes');

//["Bmw", "Mercedes","Toyota", "Hyundai", "Mazda"]

shift

removes the first item of an array.

const cars = ['Toyota', 'Hyundai', 'Mazda'];

cars.shift();

//["Hyundai","Mazda"]

pop

removes the last element of an array.

const cars = ['Toyota', 'Hyundai', 'Mazda'];

cars.pop();

//["Toyota","Hyundai"]

push

adds a new item at the end of an array.

const cars = ['Toyota', 'Hyundai', 'Mazda'];

cars.push('Bmw');

//["Toyota","Hyundai","Mazda","Bmw"]

They both look like they do the same thing, the only possible difference may be that shift/unshift focuses on adding and removing at the beginning of an array while pop/push adds and removes at the end of an array.

which is faster ?

shift and unshift re-indexes the whole array since it adds at the beginning of the array, so it takes time to re-index the array each time you add or remove an item to and from the array.

pop and push simply subtracts or adds items at the end of an array, this does not re-index the array since it either adds or subtracts from the length of the array.

This factor naturally makes pop and push a clear winner since less activities happen when a value is added.

Conclusion

just pop it 😉.