What is the easiest way in Java to map strings (Java String) to (positive) integers (Java int), so that
- equal strings map to equal integers, and
- different strings map to different integers?
So, similar ... |
I have a set of flags which are part of a huge text data file as single characters.
Before processing the file I map each flag to the id of a property ... |
I have two maps of type Map<Long, Integer>, one named "old" representing the old state of an object, and the other named "new" representing the new state of the same object.
Is ... |
I'd like to use hamcrest to assert that two maps are equal, i.e. they have the same set of keys pointing to the same values.
My current best guess is:
assertThat( affA.entrySet(), hasItems( ...
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I have a question. First, I declared a map:
Map<TwoIntClass, Set<Integer>> m = new HashMap<TwoIntClass, Set<Integer>>();
Now, I want to put stuff inside this map, something like
int num = 7;
m.put(new TwoIntClass(5, 3), ?? ...
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Given a specific set of strings, what's the best way to map them to a corresponding set of integers? Say I have a class with a few integer constants that I ... |
I have two arrays:
int[] intArray = new int[]{point1,point2,point3,point4};
String[] strArray = new String[]{worda,wordb,wordc,wordd};
Now, I want to sort intArray in numerical order, such that strArray follows the same order. I'm sure this is ... |
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I have a continuous, ordered sequence of integers that start less than zero and go above zero; for instance ...,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7. I need to map these into a repeating sequence 3,6,9,12, with ... |
If we have a Map<T, Integer>, let's say the Integer value represents "how many" Ts there are. Thus, I want to uniformly select a T based on its Integer value. If ... |
How do I map a String to a statically defined array of ints? I tried
private static Map<String, int[]> map = new HashMap<String, int[]>();
static {
map.put("foo", {5, 1, 3, ...
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TreeMap<Integer, String> map = new TreeMap<Integer, String>();
map.put(1, "example");
map.put(1, "example2");
map.put(1, "example3");
Iterator<Integer> itr = map.keySet().iterator();
...
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I want to store the IDs of items and their corresponding co-ordinates. For this, I'm using a TreeMap where Coordinates is a class containing int x and int y. Now, for ... |
Let's say I want to build a small simple map, where the key is N integers (fixed, usually one) and the value is M integers (also fixed, usually one).
Now I would ... |
A quick question which maybe is lame.
In the following code:
Map<Integer, Double[]> dataMap = new Map<Integer, Double[]>();
dataMap.put(1, new Double[]{100,100});
Double[] dob = dataMap.get(1);
dob[0] = 100;
dob[1] = 200;
dataMap.put(1, dob);
Is the last "dataMap.put" instruction necessary? ... |
I have an text and I will do some filtering based in the number of the words of each phrase.
I was thinking in using a Map, in the key I put ... |
Getting this error:
incompatible types
required: java.lang.Integer
found: java.util.Map.Entry<org.joda.time.DateTime.java.lang.Integer>
and the code resulting in error:
public static void checkRange() {
...
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is the collection going to grow at some point? will it eventually become a million or a billion or more elements? How often are elements added or deleted? Also, how often do you need to do this? if you are going to search for an element millions of times, you may do better to take the performance hit and sort it ... |
Personally i feel it would increase performance (a little) Strings have an overhead of using the string pool. So when you create a key, a lot ot stuff happens. Integers on the other hand are easier to create and destroy. Furthermore, Strings are backed by an array of characters. So a key like 11221 will be 10 byte while the same ... |
20. Mapmylist forums.oracle.com |
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First, your synchronization seems a bit lacking (unsynchronized adding/removing as far as I can see). Consider using Collections.synchronizedMap to wrap your HashMap, then you can skip all homemade synchronization as it's taken care of for you. Second, if you can, it would be a good idea to increase the memory your program has access to. The default is 64Mb, but if ... |