Get the item at the index.
This works with Maps, TreeSets, Strings, Object arrays, primitive arrays,
etc.
Implemented by:
org.boon.primitive.Byt
org.boon.primitive.Chr
org.boon.primitive.Int (in progress)
org.boon.primitive.Lng (in progress)
org.boon.Arrays
org.boon.core.Strings (planned)
org.boon.core.StrBuf (planned)
org.boon.Lists
org.boon.Maps
org.boon.Sets
Works with maps and sets
Map dogMap; //map of dogs
Dog dog = new Dog("dog");
NavigableSet set; //set of strings
List list;
char[] letters;
Initialize our examples
dogMap = map("dog", dog);
set = sortedSet("apple", "kiwi", "oranges", "pears", "pineapple");
list = list("apple", "oranges", "pears");
letters = array('a', 'b', 'c', 'd');
The methods map, list, sortedSet, arrays
are utility methods for creating Maps, lists sets, etc.
Using
//Get the dog at the index "dog" in the map
assertEquals(
dog, idx(dogMap, "dog")
);
//Get the string "oranges" at index "ora"
assertEquals(
"oranges",
idx(set, "ora")
);
//Get the string "oranges" at index "o"
assertEquals(
"oranges",
idx(set, "o")
);
//Get the string "oranges" at index 1 of the list.
assertEquals(
"oranges",
idx(list, 1)
);
// Get the string "pears" at index -1 (using Python style slice notation)
// of the list.
assertEquals(
"pears",
idx(list, -1)
);
//oranges are two from the back
assertEquals(
"oranges",
idx(list, -2));
//apple are two from the back
assertEquals(
"apple",
idx(list, -3));
Based on the example at top
UniversalOperations:
//Using idx to access a value.
assert idx( veggiesSet, "b").equals("broccoli");
assert idx( fruitList, 1 ).equals("oranges");
assert idx( fruitArray, 1 ).equals("oranges");
assert idx( letters, 1 ) == 'b';
assert idx( bytes, 1 ) == 0x2;
assert idx( favoritesMap, 2 ).equals("pineapple");
assert idx( map, "pineapple" ) == 2;
Negative index works with list like, array like things.
//Negative indexes
assert idx( fruitList, -2 ).equals("oranges");
assert idx( fruitArray, -2 ).equals("oranges");
assert idx( letters, -2 ) == 'b';
assert idx( bytes, -3 ) == 0x2;