locworks on labels in the index.ilocworks on the positions in the index (so it only takes integers).ixusually tries to behave likelocbut falls back to behaving likeilocif the label is not in the index.
loc works on labels in the index. iloc works on the positions in the index (so it only takes integers).ix usually tries to behave like loc but falls back to behaving like iloc if the label is not in the index.