How long does an opened and unrefrigerated tub of yogurt last? I have found online that unopened and unrefrigerated yogurt will last for a few days without refrigeration. However, is this also true for opened and unrefrigerated yogurt? By "opened" I mean that I have already removed the seal and taken a few spoonfuls out of the tub before leaving it unrefrigerated. 

EDIT: I see this question has been marked as duplicate. I think that the link provided does not answer my question. The case for yogurt is a very special one since it is a fermented food and cannot just be casually thrown into the general category of "dairy product" (as does the top answer in linked question). Moreover, my rough understanding is that yogurt has a low pH (from the high amounts of lactic acid) which prevents the growth of external pathogens. Hence, unopened yogurt will be safe at room temperature for at least a couple of days.  However, if you wish me to be pedantic, my question would be: is it likely that by opening the yogurt tub I introduced pathogens that can replicate rapidly at the low pH of yogurt given that it was left unrefrigerated?
When you open a food product, you are exposing it to microbes in the air. The food is sealed in a sanitary environment and bacteria is kept out. Once you open the container of yogurt, those microbes begin working on the yogurt. Further, when you leave the yogurt at room temperature the bacteria can rapidly multiply as the yogurt is in the danger zone between 40 F and 140 F. At temperatures in this range, any yogurt exposed to bacteria in the air will become rancid rather quickly.