how can I find an element of an HashMap in Java, if the HashMap is of the form and one key is empty, so it only contains a blank character.
In my example:
Let wordMap be an instance of HashMap filled with elements.
if (wordMap.containsKey("")) {
wordMap.remove("");
}
This didn´t work. I hope someone can help me.
After I did this, I convert the hash map to a tree map and sort it by the biggest Integer. I print that to the console and this is what I get with
System.out.println("results: " + tree)
I get on the console:
results: { =194, in=73, ...}
Thanks
You can do a couple of different things. For your issue, I would do:
if (wordMap.containsKey(" ")) {
wordMap.remove(" ");
}
However, to be more comprehensive I would iterate over the keys and remove any key that passes the StringUtils.isEmpty()
test.
Are you trying to retrieve the value? If yes, then you need replace that wordMap.remove(""); with wordMap.get("");
Otherwise, if you're trying to remove the Entry with a key "" that is the correct way to do it.
If you are using Java 8, then you can apply the following solution.
wordMap.entrySet()
.removeIf(e -> StringUtils.isBlank(e.getKey()));
Here StringUtils.isBlank
can be replaced with custom logic to check for invalid keys.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.