iterator - How do I modify each element in an Iterable<T> in Java? -

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• can 1 each loop in java in reverse order? 11 answers

i've searched far can , i'm struggling find answer question.. have iterable object , want modify each item in (i not want add it) new value. i've tried

for (t e : list)  {     e = a.get(index);     system.out.println(e);     index--; } 

to modify didn't work, because foreach loop. can show me i'm doing wrong code? (the idea i'm trying reverse iterable's item order.)

public class linkedlist<t> {      iterable<t> list;      public linkedlist() {} //create empty list      public linkedlist(iterable<t> iterable)      {          list = iterable;      }      @suppresswarnings("unchecked")      public iterable<t> reverse()      {          integer size = size();          list<t> = new arraylist<t>();          integer index = size - 1;          (t e : list)           {              a.add(e);          }          iterator iterator = list.iterator();          while (iterator.hasnext())           {              t element = (t)iterator.next();              element = a.get(index);              system.out.println(element);              index--;          }          return list;      } } 

you need understand loop construct:

for (t e : list) 

this assigns variable e, copy of reference object in list.

you tried assign new value e:

e = a.get(index); 

but achieves overwriting copy of reference. list list continues use reference has used.

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your end goal return iterable travels in reverse direction? have few options here.

• keep underlying list unchanged, make custom iterator provide reverse view on it. iterator can supply iterable<t>, return.
• shuffle around contents of underlying list, such list itself in reverse order (you can use collections.reverse(list) this). natural iteration order resemble "reverse" iteration of original list.
• same above, instead of mutating existing list: create reversed copy of list.

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one thing you're doing make hard this:

iterable<t> list; public linkedlist(iterable<t> iterable) {     list = iterable; } 

does need accept specific iterable? instead accept list (giving ability lookup elements @ index)? if has iterable, may not have store iterable. insert contents arraylist, , variable list list.