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Suppose there are two HashMaps as follows:
HashMap<String, Integer> h1 = [{"a":1}, {"b":2}, {"c":3}];
HashMap<String, Integer> h2 = [{"k": 1}, {"f": 4}, {"g":5}, {"a":10}]
The multiplication is just like a simple vector multiplication, in this case it will return
1*10 + 2*0 + 3*0 = 10.
That is if the keys are same, then only multiply the two respective values.
Result -> It should return an integer.
int result = 0;
for(String s : h1.keySet()){
if(h2.containsKey(s)){
result = result + h2.get(s) * h1.get(s);
}
}
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List<Integer> list = Arrays.asList(1, 2, 4, 5,7, 8, 9);
int n = 3;
When user input integer as 3 then program should result as 2 and 4 in an above given list.
You can use Collectors.partitioningBy:
Map<Boolean, List<Integer>> m = list.stream()
.filter(i -> i != n)
.collect(Collectors.partitioningBy(i -> i > n));
Integer lower = m.get(false).get(m.get(false).size() - 1);
Integer higher = m.get(true).get(0);
Additional check whether both m.get(false) and m.get(true) are not empty might be needed.
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I have been working with while loops however I cant seem to understand how the remainder works inside this code.
int a = 10;
while( a <= 1000 && a % 100 != 0){
System.out.println("a = " + a);
a = a + 10;
}
a & 100 != 0
Performs bitwise and , then compares the result to 0. It will be false even in the first iteration, since 10 & 100 = 0
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Does such convention exist?
For example, I have a predicate: Predicate<Integer> predicate = i -> (i < 1); or BiFunction<String, String, String> function = (x, y) -> x + y;. How should I name it so the variable's type and sense would be clear?
There are no specific naming conventions for functional interfaces. Just name them according to what they do:
Predicate<Integer> smallerThanOne = i -> (i < 1);
BiFunction<String, String, String> concatenate = (x, y) -> x + y;
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I'm java beginner, This is my code.
int [] arr = {1,3,4,5,5,6};
I want to get each array values separately for calculation. can you please help me.
For example: I want first two digits (array index 0 and 1) only how to get that.
to get the first and second item, do like this:
int [] arr = {1,3,4,5,5,6};
System.out.println("pos 0: "+arr[0]+" pos 1: "+arr[1]);
by doing arr[n-1], you select the 'n'th value in the array.
now, if you want to multiply these first two values..:
int result = arr[0] * arr[1]; // 1 * 3
System.out.println(result) // 3
For example: I want to multiply first two digit (1*3) after that (4*5) like that.. so I want to get these values separately.
To do this,
int [] arr = {1,3,4,5,5,6};
int ans;
for(int i=0;i<6;i+=2){
ans = arr[i]*arr[i+1];
System.out.println(""+ans);
}
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If I have some initialized integers which are instance variables, for example:
int x = 0;
int y = 0;
Is there a way I could create an array with all of the integers without doing:
int[] array = {x, y};
I would like to not have to add the integers into the array manually.
If the variables are initialized to 0, then just create the array with the appropriate size:
int[] array = new int[10];
All elements in the array are initialized to 0.