Financial questions that need an answer

My neighborhood is in transition from Puerto Rican to yuppy and I can’t stand those white yuppies. I rented to one before and they whine and complain. The refrigerator door is on the wrong side, the heater makes too much noise, the tenant upstairs walks around too late at night, it smells like garbage in the back hallway, the neighbors dog is barking too loud, well you get the picture. White people, especially yuppies, whine so freaking much. It’s like they think because they have money their crap doesn’t smell. They want everything to be perfect and are always waking me up at night. I am willing to charge less rent for a nice Puerto Rican family but these freakin yuppies keep answering my ads. How can I rent to whomever I choose without being accused of discrimination? Can I place a cap on what income my doable tenant has?