within the objects referenced by and dchanging the shared list from makes it look different from and dtoo store the same reference in more than one place (variableslistsand so onthis is feature--you can pass large object around program without generating expensive copies of it along the way if you really do want copieshoweveryou can request themslice expressions with empty limits ( [:]copy sequences the dictionarysetand list copy method ( copy()copies dictionarysetor list (the list' copy is new as of some built-in functionssuch as list and dict make copies (list( )dict( )set( )the copy standard library module makes full copies when needed for examplesay you have list and dictionaryand you don' want their values to be changed through other variablesl [ , , {' ': ' ': to prevent thissimply assign copies to the other variablesnot references to the same objectsa [: copy(instead of (or list( )instead of (ditto for setsthis waychanges made from the other variables will change the copiesnot the originalsa[ 'nib[' ''spamld ([ ]{' ' ' ' }core types review and summary