If you want to do it with events you can give the animations number names like (1,2,3,...). Or even better numbers in combination with a word like (run1,run2,run3...). Then you can use the set animation action with the expression "run"&n where n is an index.
If you want to do it in a plugin with the javascript sdk then look here:
https://www.scirra.com/manual/29/object-type
If the object has animations you can use something like type.animations[0] to get the name at index i. You can glean more info about it by looking at the sprite object's source.