What's the best way to iterate over the items in a HashMap
?
If you're only interested in the keys, you can iterate through the keySet()
of the map:
Map<String, Object> map = ...;
for (String key : map.keySet()) {
// ...
}
If you only need the values, use values()
:
for (Object value : map.values()) {
// ...
}
Finally, if you want both the key and value, use entrySet()
:
for (Map.Entry<String, Object> entry : map.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
// ...
}
One caveat: if you want to remove items mid-iteration, you'll need to do so via an Iterator (see karim79's answer). However, changing item values is OK (see Map.Entry
).