miscellaneous topics iii in this we examine variety of useful topics mutability and references if is list and is stringthen [ gives the first element of the list and [ the first element of the string if we want to change the first element of the list to [ ]= will do it but we cannot change string this way the reason has to do with how python treats lists and strings lists (and dictionariesare said to be mutablewhich means their contents can change stringson the other handare immutablewhich means they cannot be changed the reason strings are immutable is partly for performance (immutable objects are fasterand partly because strings are thought of fundamental in the same way that numbers are it makes some other aspects of the language easier as well making copies another place that lists and strings differ is when we try to make copies consider the following codes 'hello copy '!!print' is now'ss is nowhello!!copy'copycopyhello in the code above we make copy of and then change everything works as we would intuitively expect now look at similar code with listsl [ , , copy