I will take the dandelions over Oxalis any day! If you mow down an oxalis in the grass, every place a flower lands will drop a seed which turns into a pea sized bulb which turns into a clump, which gets mowed down and the cycle continues till you have clumps all over your yard. The pea sized bulbs multiply and sends down a tap root six inches down and then it starts growing bulbs at the end of the tap root. So if you pull it up you will never get it all. The dandelions are easy with a garden weasel.
If you can't dig up the dandelions just pick off the little balls that have the helicopter seeds.