Combining Lists

The extend() Method extend() vs append() Choosing the wrong method when combining lists is one of the most frequent sources of nested-list bugs. Keep these rules in mind as you work with multi-source data. extend() with Any Iterable Notice what happened with the string "cd": each character became a separate item in the list. This is because strings are iterable, and iterating over a string yields individual characters. This behavior can be surprising if you expected the whole string to be added as one item. + Operator: Concatenation The += Operator * Operator: Repetition Slicing and combining operations give you the flexibility to reshape list data before passing it to functions, merging datasets, or preparing output for display.