5. Adding new elements to DataSeries

Since all the elements of DataSeries are expected to have keys, in order to add a new element you must specify a key that should be associated with it

series add: 'x' atKey: #k4.

In future there will also be an add: message that will choose a default key value or even predict the next element of a sequence of keys. For example, if keys are #(1 2 3 4 5), the new element will be associated with key 6, if the sequence of keys is #(2 4 6), the next key will be 8. Perhaps, it will even be possible to predict the next key in symbolic sequences, such as #(a b c d) or #(k1 k2 k3). Such functionality is not easy to implement, so we leave it for future releases of DataFrame library.

Another way of adding an element to DataSeries is by using the atKey:put: message with a non-existing key. Inspired by Pandas, atKey:put: modifies an element at a given key if such key exists in a DataSeries, or adds a new element associeted with that key, if it wasn't found.

series atKey: #k4 put: 'x'.

Keep in mind that both add:atKey: and atKey:put: messages don't create a new series, but modify the existing one. So use them with caution.