java - Convert an loop (while and for) to stream -

i have started working java 8 , trying convert loops , old syntax in code lambdas , streams.

so example, i'm trying convert while , loop stream, i'm not getting right:

list<string> list = new arraylist<>(); if (!oldlist.isempty()) {// old list<string>     iterator<string> itr = oldlist.iterator();     while (itr.hasnext()) {         string line = (string) itr.next();         (map.entry<string, string> entry : map.entryset()) {             if (line.startswith(entry.getkey())) {          string newline = line.replace(entry.getkey(),entry.getvalue());                 list.add(newline);             }         }     } } 

i wanted know if it's possible convert above example single stream there while loop inside of loop.

as stated above, using streams here doesn't add value since makes code harder read/understand. you're doing more learning exercise. being said, doing more functional-style approach doesn't have side effect of adding list within stream itself:

list = oldlist.stream().flatmap(line->             map.entryset().stream()                     .filter(e->line.startswith(e.getkey()))                     .map(filteredentry->line.replace(filteredentry.getkey(),filteredentry.getvalue()))         ).collect(collectors.tolist()); 

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