Можно ли отредактировать значение в переменной?

$var = '12345'

$var = '234'

StringLeft 
StringRight
StringTrimLeft 
StringTrimRight 
StringMid

$var = '12345'
$var = StringTrimLeft($var, 1)
$var = StringTrimRight($var, 1)
MsgBox(0, "Test:", $var)

$var = '12345'
$var = StringMid($var, 2, 3)
MsgBox(0, "Test:", $var)

$var = '12345'

$var = '0123459'

$var = '12345'
$var_0 = '0'
$var_9 = '9'

MsgBox(0, "Test:", $var_0 & $var & $var_9)

$var = '12345'
$var = '0'&$var&'9'

$var = "'"
MsgBox(0, "Test:", $var)