Joining a List<String> in Java with commas and "and"
Given a list
List<String> l = new ArrayList<String>();
l.add("one");
l.add("two");
l.add("three");
I have a method
String join(List<String> messages) {
if (messages.isEmpty()) return "";
if (messages.size() == 1) return messages.get(0);
String message = "";
message = StringUtils.join(messages.subList(0, messages.size() -2), ", ");
message = message + (messages.size() > 2 ? ", " : "") + StringUtils.join(messages.subList(messages.size() -2, messages.size()), ", and ");
return message;
}
which, for l, produces "one, two, and three". My question is, is there a standard (apache-commons) method that does the same?, eg
WhatEverUtils.join(l, ", ", ", and ");
To clarify. My problem is not getting this method to work. It works just as I want it to, it's tested and all is well. My problem is that I could not find some apache-commons-like module which implements such functionality. Which surprises me, since I cannot be the first one to need this.
But then maybe everyone else has just done
StringUtils.join(l, ", ").replaceAll(lastCommaRegex, ", and");
Solution 1:
In Java 8 you can use String.join()
like following:
Collection<String> elements = ....;
String result = String.join(", ", elements);
Solution 2:
With Java 8, you can use streams with joiners.
Collection<String> strings;
...
String commaDelimited = strings.stream().collect(Collectors.joining(","));
// use strings.parallelStream() instead, if you think
// there are gains to be had by doing fork/join