Re: Java Collections List : Converting from List '<Column <String1, String2>>' to 'List <String1>'

From:
Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups:
comp.lang.java.help
Date:
Sat, 19 Feb 2011 08:01:40 -0500
Message-ID:
<ijof0n$2f4$1@news.eternal-september.org>
On 2/19/2011 7:05 AM, asil klin wrote:

I have a function that returns a list like this:-

List<Column<String1, String2>>

Next I want to pass this list to a 2nd function, but 2nd function just needs a list which contains only 1st part (string1) of the Column(s) of the above list.

So I want pass just this list to 2nd function:-

List<String1>

What would be the best way to do this ??


     You'll need to build a new List<String> and populate it by
extracting data from the given list. It would look something like
this (I'm inventing a few methods and names):

    List<Column<String1,String2>> original = ...;
    List<String1> reduced = new ArrayList<String1>(original.size());
    for (Column<String1,String2> col : original) {
        String1 first = col.getFirst();
        reduced.add(first);
    }

There are, of course, about one and a half gazillion different ways
to rearrange and repackage this logic, but one way or another you'll
have to do something like it. As far as I know, Java has no `mapcar'.

--
Eric Sosman
esosman@ieee-dot-org.invalid

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