On Mar 27, 4:39 am, TP <tribulati...@paralleles.invalid> wrote: > Hi everybody, > > Be a the following list, containing list elements which second field is a > string. > > >>> a = [ [4, "toto"], [5, "cou"] ] > >>> a[0][1]="tou" > >>> a > > [[4, 'tou'], [5, 'cou']] > > OK. > > Now, I want: > * to do the same modification on the list "a" within a function > * not to hardcode in this function the position of the string in each > element of a. > > At first sight, we think at defining a function like this: > > def assign( text_accessor, list_elem, new_textvalue ): > > text_accessor( list_elem ) = new_textvalue > > and then doing: > > assign( lambda elem: elem[1], a[0], "co" ) > > But it does not work, we obtain: > > text_accessor( list_elem ) = new_textvalue > SyntaxError: can't assign to function call > > In fact, we should work on the address of text_accessor( list_elem ). How to > do that?
There is always the __setitem__ method, either bound to the object in question, or along with an instance and its class. >>> def f( fun, ind, val ): ... fun( ind, val ) ... >>> a= [ None ] >>> f( a.__setitem__, 0, 'abc' ) >>> a ['abc'] Or, you could require your instances to all have a method name to accomplish it, or use operator.__setitem__. -- http://mail.python.org/mailman/listinfo/python-list
