Variable for number of players in a certain world?

[TimmoPlays]

I'm working on a GUI menu for a mini game that I'm scripting and I was wondering if there's any variable that is replaced with the number of players in a specific world. Thanks!

This is what I have so far:

command /battles:
    trigger:
        open chest with 6 rows named "&8Battles" to player
        wait 1 tick
        format slot 10 of player with iron sword named "&eClassic" with lore "&81v1||||&7Classic 1v1 battle with an iron||&7sword and iron armour.||||&f%THE VARIABLE I NEED% playing."

 

[DaviPatrick]

#More than 1 worlds
set {variable} to number of players in world "WORLD1" and "WORLD2"

#Only 1 world
set {variable} to number of players in world "WORLD"

 

[TimmoPlays]

#More than 1 worlds
set {variable} to number of players in world "WORLD1" and "WORLD2"

#Only 1 world
set {variable} to number of players in world "WORLD"

Thank you so much!

 

[DaviPatrick]