Clear Hash or overwrite value ?

[Vladadamm]

What's the most efficient between :

1. Clear Hashtable then Save new values

2. Save new values without clearing hash

(in the case that i need to change all the value)

 

[Maker]

You can save new values without clearing the hash.

 

[Arhowk]

It depends. If your saving new values to different keys of the hashtable and not using your previously written keys, than you should clear the hash before saving. If you're overwriting keys, than you can just overwrite them and not worry about clearing

 

[IsaacNewbton]

i have a related question

Do hashtables reserve a set amount of memory or do they grow dynamically? Like arrays always take up the space for 8192 entries even if they are not that big?

 

[Arhowk]

1) Please do not ask questions in threads other than your own

2) Variable arrays do not allocate space for all 8192 entries if the maximum array size is 1 or not defined

3) They grow dynamically, meaning the space for the key isnt allocated untill it is saved

 

[WaterKnight]

How much memory shall this be, allocating a whole hashtable. Variable arrays are always usable from 0 to 8190/8191 but afaik if you have not used the higher areas yet, it gets mallocated in powers of 2 like

...
using index 16 or higher up to 32-1
using index 32 or higher up to 64-1
using index 64 or higher up to 128-1
...

hardly matters though