Android Question String optimization

[Alessandro71]

Having a lot of string building statement, I was asking myself what is the best way to handle that, from a performance and memory handling perspective:

newstring = "constant string" & variablestring

or

newstring = $"constant string${variablestring}"$

both produce the same result, but which one generates the best code and runtime performance?

 

[Daestrum]

I would guess the & version - it produces less java code

' &
_newstring1 = "constant string"+_variablestring;
' smartstring
_newstring2 = ("constant string"+anywheresoftware.b4a.keywords.Common.SmartStringFormatter("",(Object)(_variablestring))+"");

 

[Sagenut]

Not sure about what I am about to write, but...
Regular string are Immutable.
So trying to modify it will, with a concatenation with & for example, anyway create an additional new string.
To avoid this it should be used the StringBuilder that will manage mutable string and will effectively reuse the same string.
Here the documentation:
https://www.b4x.com/android/help/core.html#stringbuilder

 

[Alessandro71]

yes, but my use case is not about changing an existing string, rather than creating a new one from exiting ones

 

[emexes]

Having a lot of string building statement

my use case is ... creating a new one from existing ones

Why not StringBuilder? ("especially useful for when you need to concatenate many strings")

 

[Erel]

both produce the same result, but which one generates the best code and runtime performance?

The performance difference, if there is one, is negligible = no user will ever feel any difference. Use the one that you feel that is simpler.

If you are building very large strings then you should use StringBuilder.