In Python 3 there is no cmp argument for the sorted function (nor for list.sort). According to the docs, the signature is now sorted(iterable, *, key=None, reverse=False), so you have to use a key function to do a custom sort. The docs suggest: Use functools.cmp_to_key() to convert an old-style cmp function to a key function. … Read more
I suggest you use the builtin method Double.compare(). If you need a range for double values to be equal you can use chcek for that first. return Double.compare(p1.getY(), p2.gety()); or if(Math.abs(p1.getY()-p2.getY()) < ERR) return 0; return Double.compare(p1.getY(), p2.gety()); The problem with using < and > is that NaN will return false in both cases resulting … Read more
Handle it like null means infinitely far away. Thus: comp(1234, null) == -1 comp(null, null) == 0 comp(null, 1234) == 1 With this, you get a consistent ordering.
In java the “natural” order meaning is “lexicographical” order, so there is no implementation in the core like the one you’re looking for. There are open source implementations. Here’s one: NaturalOrderComparator.java Make sure you read the: Cougaar Open Source License I hope this helps!
First, all the examples you say cause errors compile fine with the reference implementation (javac from JDK 8.) They also work fine in IntelliJ, so its quite possible the errors you’re seeing are Eclipse-specific. Your underlying question seems to be: “why does it stop working when I start chaining.” The reason is, while lambda expressions … Read more
Found a possible solution: Comparator.comparing(ToSort::getSortBy, Comparator.nullsFirst(Comparator.naturalOrder()) )
The exception message is actually pretty descriptive. The contract it mentions is transitivity: if A > B and B > C then for any A, B and C: A > C. I checked it with paper and pencil and your code seems to have few holes: if (card1.getRarity() < card2.getRarity()) { return 1; you do … Read more
Use Comparable if you want to define a default (natural) ordering behaviour of the object in question, a common practice is to use a technical or natural (database?) identifier of the object for this. Use Comparator if you want to define an external controllable ordering behaviour, this can override the default ordering behaviour. See also: … Read more
Follow this code to sort any ArrayList Collections.sort(myList, new Comparator<EmployeeClass>(){ public int compare(EmployeeClass obj1, EmployeeClass obj2) { // ## Ascending order return obj1.firstName.compareToIgnoreCase(obj2.firstName); // To compare string values // return Integer.valueOf(obj1.empId).compareTo(Integer.valueOf(obj2.empId)); // To compare integer values // ## Descending order // return obj2.firstName.compareToIgnoreCase(obj1.firstName); // To compare string values // return Integer.valueOf(obj2.empId).compareTo(Integer.valueOf(obj1.empId)); // To compare integer … Read more
Is the array sort callback function called many times during the course of the sort? Yes If so, I’d like to know which two numbers are passed into the function each time You could find out your self with: array.sort((a,b) => { console.log(`comparing ${a},${b}`); return a > b ? 1 : a === b ? … Read more