functions are called using parentheses and passing zero or more argumentsoptionally assigning the returned value to variableresult (xyzg(almost every object in python has attached functionsknown as methodsthat have access to the object' internal contents they can be called using the syntaxobj some_method(xyzfunctions can take both positional and keyword argumentsresult (abcd= ='foo'more on this later variables and pass-by-reference when assigning variable (or namein pythonyou are creating reference to the object on the right hand side of the equals sign in practical termsconsider list of integersin [ ] [ suppose we assign to new variable bin [ ] in some languagesthis assignment would cause the data [ to be copied in pythona and actually now refer to the same objectthe original list [ (see figure - for mockupyou can prove this to yourself by appending an element to and then examining bin [ ] append( in [ ] out[ ][ figure - two references for the same object understanding the semantics of references in python and whenhowand why data is copied is especially critical when working with larger data sets in python the basics www it-ebooks info