AutoHotkey Intro 12 - Playing With Variables hints and tricks

Here we take a quick look on how to clean up your variables in your script

CODE:
#MaxMem 256
VarSetCapacity(MyVar, 10240000) ; ~10 MB

stringvar=
clipboard=
stringvar=%stringvar%
stringvar=%stringvar% `n %var%

;REGex to remove all letters
f1::
stringvar= todays date is 12/31/2020 which is a thursday.
stringvarnew := RegExReplace(stringvar, "[a-zA-Z]", "")
msgbox, %stringvarnew%
Return

;max lenght in string
f2::
stringvar= Hello today is a great day and i would like to look at kittens
StringLeft, stringvar, stringvar, 20
msgbox, %stringvar%
Return

;Check lenght
F3::
stringvar = I am just
Length := StrLen(stringvar)
If Length greaterorlessersignhere 10
{
msgbox, string is to long
}
else
{
msgbox, string is OK
}
Return
;StringLen, OutputVar, InputVar old way

;removing words punc.
f4::
stringvar= hi order# 5165!
StringReplace, stringvar, stringvar, order#, , All
StringReplace, stringvar, stringvar, !,, All
varremove=hi
StringReplace, stringvar, stringvar, %varremove%, , All
msgbox, %stringvar%
return

f5::
stringvar= this line needs to be all caps
StringUpper, stringvar, stringvar,
msgbox, %stringvar%
Return

f6::
stringvar= tHis lINe HaS ranDOM CAps
StringUpper, stringvar, stringvar, T
;StringLower, stringvar, stringvar, T
msgbox, %stringvar%
return

f7::
Colors := "red,green,blue"
ColorArray := StrSplit(Colors, ",")
Loop % ColorArray.MaxIndex()
{
this_color := ColorArray[A_Index]
MsgBox, Color number %A_Index% is %this_color%.
}
Return

[parlabaneisback]

Interesting video - thanks. I still get confused about the % signs around variables - sometimes there aren't any, sometimes just a preceding one followed by a space, sometimes the variable name is encased in them. Any clarification would be great.