Humans are able to deal with various types of values. Machine learning algorithms with some exceptions need numerical values. If we offer a string such as Ivan, unless we are using specialized software the program will not know what to do. In this example, we are dealing with a categorical feature, names probably. We can consider each unique value to be a label. (In this particular example, we also need to decide what to do with the case-is Ivan the same as ivan). We can then replace each label by an integer-label encoding. This approach can be problematic, because the learner may conclude that there is an ordering.