Since you locked other thread about the isNumber function, I'll share you one that works well for me:
function isNumber(%n)
if(%n !$= %n * 1)
{
return 0;
}
return 1;
}
Only caveat about it is that it won't work for larger numbers since numbers over 1 million get put in scientific notation and numbers that have over 6 digits in them (ex: -0.5312316) get shortened internally, so it's best used for integers or any other case that shouldn't need to have many digits.