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How to compare objects by multiple fields in Java?
(from Ways to sort lists of objects in Java based on multiple fields) Java 8 solves this nicely by lambda’s (though Guava and Apache Commons might still offer more flexibility): Collections.sort (reportList, Comparator.comparing (Report::getReportKey) .thenComparing (Report::getStudentNumber) .thenComparing (Report::getSchool));
What happens if the reference object and the difference object are the same?
If the reference object and the difference object are the same, there’s no output, unless you use the IncludeEqual parameter. If the objects are different, Compare-Object wraps the differing objects in a PSCustomObject wrapper with a SideIndicator property to reference the differences.
How does compare-object check for available methods?
One set of objects is the reference, and the other set of objects is the difference. Compare-Object checks for available methods of comparing a whole object. If it can’t find a suitable method, it calls the ToString () methods of the input objects and compares the string results. You can provide one or more properties to be used for comparison.
How to know if two objects are equal?
The Equals method and the IEquatable interface could be used to know if two objects are equal but they won’t allow you to know the differences between the objects. You could use reflection by comparing each property values.
How to compare two objects in C # 9?
If you have a requirement where you want the class which is immutable. I mean that none of the properties can be modified once it’s been created. In that case, C# 9 have a feature which is called a record. You can easily compare records by values and types is they are equal.
Can you compare two objects with the same PersonID?
However, the same distinction can also apply at a domain level. Suppose that your Person class has a PersonId property, unique per distinct real-world person. Should two objects with the same PersonId but different Age values be considered equal or different?
When do you need multiple comparators in Java?
The multiple comparators was only if you want different comparison methods that are not a function of the data itself – i.e. sometimes you want to compare by name, other times by age, etc. To compare by multiple fields at the same time, only one comparator would be necessary. – Elie Nov 13 ’14 at 17:13