java-stream

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 11 days ago . Improve this question I have a class like class Employee String id String name I want to filter out the list of employees based on the list of deptId which is an integer list Employee emp1 = new Employee("1","Ally"); Employee emp2 = new Employee("2","Billy"); ArrayList<Employee>

问题 i want to determine the of the "columns" in "rows" or or better: Build sum of a list of maps like List> rows Is it somehow possible to sum all values of each distinct column? The function shall return a Map with the column as key and the sum of all values as value. summMap.get("columname") Let's assume i have the following list of maps: List<Map<String, Long>> mapList = new ArrayList(); Map<String, Object> map1 = new HashMap<>(); Map<String, Object> map2 = new HashMap<>(); Map<String, Object>

问题 i want to determine the of the "columns" in "rows" or or better: Build sum of a list of maps like List> rows Is it somehow possible to sum all values of each distinct column? The function shall return a Map with the column as key and the sum of all values as value. summMap.get("columname") Let's assume i have the following list of maps: List<Map<String, Long>> mapList = new ArrayList(); Map<String, Object> map1 = new HashMap<>(); Map<String, Object> map2 = new HashMap<>(); Map<String, Object>

问题 This question already has answers here : Find maximum, minimum, sum and average of a list in Java 8 (3 answers) Closed last year . I have List of Integres and want get min, max and avg from list to Map. Below is my code, List<Integer> numbers = Arrays.asList(-2, 1, 2, 3, 5, 6, 7, 8, 9, 10, 100); int min = numbers.stream().mapToInt(n -> n).min().getAsInt(); int max = numbers.stream().mapToInt(n->n).max().getAsInt(); double avg = numbers.stream().mapToInt(n->n).average().getAsDouble(); Map

问题 This question already has answers here : Filter values only if not null using lambda in Java8 (6 answers) Closed 4 years ago . I'm new in using map and filters in Java 8. I'm currently using Spark ML library for some ML algorithms. I have the following code: // return a list of `Points`. List<Points> points = getPoints(); List<LabeledPoint> labeledPoints = points.stream() .map(point -> getLabeledPoint(point)) .collect(Collectors.toList()); The function getLabeledPoint(Point point) returns a