I have a set of strings that I'd like to iterate over, and change all of those who equal something, to equal something else:
// Set<String> strings = new HashSet()
for (String str : strings) {
if (str.equals("foo")) {
// how do I change str to equal "bar"?
}
}
I've tried replace() which didn't work. I've also tried removing "str" and adding the desired string, which caused an error. How would I go about doing this?
Two points:
A Set means "only one copy of each". What's the "change all" stuff? Why do you have to iterate over the Set? Why won't this do it?
strings.remove("foo");
strings.add("bar");
Since Set can't have duplicates, what you are trying to do is a bit strange. Why iterate?
if (strings.contains("foo")) {
strings.remove("foo");
strings.add("bar");
}
Make sure that whole block is synchronized properly if that strings set is shared between threads.
You should not change the set while iterationg over it.
Better try this:
Set<String> strings = new HashSet();
strings.add("foo");
strings.add("baz");
Set<String> stringsNew = new HashSet();
for (String str : strings) {
if (str.equals("foo")) {
stringsNew.add("bar");
} else {
stringsNew.add(str);
}
}
System.out.println(stringsNew);
If you change your HashSet in the middle of iteration, you get ConcurrentModificationException. That means, you have to remove "foo" first, and then add "bar" - outside iterator
A set is a collection that contains no duplicate objects. Therefore if you wish to 'replace' an object in a set with something else, you can simply remove it first, and then add the string you wish to 'replace' it with.
// Set<String> s = new HashSet();
for (String str : s) {
if (str.equals("foo")) {
s.remove(str);
s.add("bar");
}
}
