How to write a CSS Conditional in ember for class attributes?

am stuck on a problem and haven't been able to find a resource that explains this. Sorry if this is obvious but I am an ember newbie.

I want to be able to write an if equals conditional for a table.

Example:

if (data === 'r') {
     change table row to red
else 
    change table row to blue
}

I've been trying by using the following code:

<table class="attr1  red  blue ">
</table>

Any help is appreciated.