How To Take A Fundamental Value Twain Or Entry From Hashmap Inwards Coffee 8
In the concluding article, I guide maintain shown how to take key/value pairs from a map inwards Java based upon some weather similar take all entries where values are greater than some values. I guide maintain told you lot that you lot must work the Iterator's remove() method for removing mapping acre iteration to avoid ConcurrentModificationException, but that's non required anymore inwards Java 8. From JDK 8 onwards, you lot tin selectively take mapping without iterating over Map. The JDK 8 API has added several novel methods to existing interfaces e.g. java.util.Collection, java.util.Map, Comparator etc because the interface tin directly incorporate concrete methods inwards cast of static together with default methods.
One of such methods is removeIf() method of Collection bird which allows you lot to take entries based upon some status or predicate.
It takes a lambda expression, which tin locomote used to render the predicate you lot want. For example, you lot tin rewrite the to a higher house code inwards Java 8 every bit shown inwards the next example:
Since hither nosotros request to compare values, I guide maintain called the values() method which returns a collection of values.
Once you lot got that, you lot tin only call removeIf() method which takes a Predicate. Just locomote past times the status you lot desire to banking concern jibe for removing values from the map. Btw, if you lot are non familiar amongst novel functional programming API added on Java 8 together with so I propose you lot to outset become through a comprehensive together with up-to-date Java class like The Complete Java MasterClass on Udemy.
It covers all of import topics for Java developer together with likewise regularly updated to the latest Java versions. It's likewise really inexpensive together with you lot tin acquire it inwards precisely $10 on several Udemy flash sales which happens all some the year.
Btw, If you lot desire to testify keys from the Map for removing the mapping, you lot tin precisely telephone phone the keySet() or entrySet() methods together with apply the removeIf() telephone phone every bit shown below:
Also hither is to a greater extent than code to re-create glue together with elbow grease yourself:
You tin encounter how tardily it is to take key-value pairs based upon some status inwards Java. You tin work the newly added removeIf() method from Collection to hit that.
So, all nosotros did on our whole program, you lot tin only create it inwards precisely 1 occupation inwards Java 8. That's the beauty of Java 8. I strongly propose you lot read a adept mass on Java 8 e.g. Java 8 inwards Action to acquire to a greater extent than of such useful tricks.
That's all nearly how to take a key-value brace from a HashMap inwards Java 8. You tin encounter that directly you lot tin safely take entries based upon some weather without iterating over them, thence you lot don't request to work the Iterator's remove() method to avoid ConcurrentModificationException inwards Java acre removing entries from HashMap.
Further Learning
The Complete Java MasterClass
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Thanks for reading this article so far. If you lot similar this article together with so delight portion amongst your friends together with colleagues. If you lot guide maintain whatever questions or suggestions together with so delight drib a comment.
One of such methods is removeIf() method of Collection bird which allows you lot to take entries based upon some status or predicate.
It takes a lambda expression, which tin locomote used to render the predicate you lot want. For example, you lot tin rewrite the to a higher house code inwards Java 8 every bit shown inwards the next example:
Since hither nosotros request to compare values, I guide maintain called the values() method which returns a collection of values.
Once you lot got that, you lot tin only call removeIf() method which takes a Predicate. Just locomote past times the status you lot desire to banking concern jibe for removing values from the map. Btw, if you lot are non familiar amongst novel functional programming API added on Java 8 together with so I propose you lot to outset become through a comprehensive together with up-to-date Java class like The Complete Java MasterClass on Udemy.
It covers all of import topics for Java developer together with likewise regularly updated to the latest Java versions. It's likewise really inexpensive together with you lot tin acquire it inwards precisely $10 on several Udemy flash sales which happens all some the year.
Btw, If you lot desire to testify keys from the Map for removing the mapping, you lot tin precisely telephone phone the keySet() or entrySet() methods together with apply the removeIf() telephone phone every bit shown below:
Also hither is to a greater extent than code to re-create glue together with elbow grease yourself:
System.out.println("map earlier removing values: " + priceMap); priceMap.entrySet().removeIf( e -> e.getValue().compareTo(Double.valueOf(39.00)) > 0); System.out.println("map afterward removing values: " + priceMap); Output: map earlier removing values: {Java SE 8 for Really Impatient=31.99, Head First Design Pattern=39.05, Java Concurrency In Practice=30.67, Effective Java=41.79, Head First Java=29.02} map afterward removing values: {Java SE 8 for Really Impatient=31.99, Java Concurrency In Practice=30.67, Head First Java=29.02}
You tin encounter how tardily it is to take key-value pairs based upon some status inwards Java. You tin work the newly added removeIf() method from Collection to hit that.
So, all nosotros did on our whole program, you lot tin only create it inwards precisely 1 occupation inwards Java 8. That's the beauty of Java 8. I strongly propose you lot read a adept mass on Java 8 e.g. Java 8 inwards Action to acquire to a greater extent than of such useful tricks.
That's all nearly how to take a key-value brace from a HashMap inwards Java 8. You tin encounter that directly you lot tin safely take entries based upon some weather without iterating over them, thence you lot don't request to work the Iterator's remove() method to avoid ConcurrentModificationException inwards Java acre removing entries from HashMap.
Further Learning
The Complete Java MasterClass
books)
Thanks for reading this article so far. If you lot similar this article together with so delight portion amongst your friends together with colleagues. If you lot guide maintain whatever questions or suggestions together with so delight drib a comment.
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