Quickest way to change a pair of parenthesis to brackets in vim

Question

I am new to vim and in the process of discovering tons of interesting things that one can using this powerful editor.

One particular thing that I need to do very fr

Answer 1

Without any plugin it can be done by deleting the content inside the parenthesis and yanking in the new bracket (from anywhere within the bracket):

di(a[]P%2X

Obviously more key that using surround but but not that many ;-)

Note

There is no need to remember the sequence of key but only to start by deleting the inside of the brackets. Then it's just normal vim fu.