modifying lists you can modify the content of list as needed modifying list means to change particular entryadd new entryor remove an existing entry to perform these tasksyou must sometimes read an entry the concept of modification is found within the acronym crudwhich stands for createreadupdateand delete here are the list functions associated with crudappend()adds new entry to the end of the list clear()removes all entries from the list copy()creates copy of the current list and places it in new list extend()adds items from an existing list and into the current list insert()adds new entry to the position specified in the list pop()removes an entry from the end of the list remove()removes an entry from the specified position in the list the following steps show how to perform modification tasks with lists this is hands-on exercise as the book progressesyou see these same functions used within application code the purpose of this exercise is to help you gain feel for how lists work open python shell window you see the familiar python prompt type list [and press enter python creates list named list for you notice that the square brackets are empty list doesn' contain any entries you can create empty lists that you fill with information later in factthis is precisely how many lists start because you usually don' know what information they will contain until the user interacts with the list type len(list and press enter the len(function outputs as shown in figure - when creating an applicationyou can check for an empty list using the len(function if list is emptyyou can' perform tasks such as removing elements from it because there is nothing to remove type list append( and press enter