通过字符串搜索数组列表

Question

One problem that I am facing in my code is that I have a long list of strings that map to different integers. For example, "Apple" maps to 4, "Bat" maps to 7, etc. Is there any ways to create an Array List such that a string is used as the input search element rather than a traditional number? Ie. Array["Apple"] instead of Array[4]

Answer 1

ArrayList doesn't have that support. But Hashmaps can solve your usecase. Check that out.

Answer 2

Use an associative data structure for this.

Map<String, Integer> items = new HashMap<>();
items.put("Apple", 4);
items.put("Bat", 7);

items.get("Apple");
items.get("Bat");

Answer 3

You can use a Map to solve your use case.

Map<String, Integer> fruits = new HashMap<String, Integer>();

Now your fruits Map will have the String as a key and Integer as a value.

To put key-value: fruits.put("Apple", 1)
To get value based on key: fruits.get("Apple")

Answer 4

You will need two data structures for this problem: a Map to associate item names with indices and a List to store the items (eg an ArrayList ). For example (untested):

// Store the items and a mapping of their indices by name.
List<String> items = new ArrayList<String>();
Map<String, Integer> itemIndices = new HashMap<String, Integer>();
// Add the item to both data structures.
itemIndices.put("Apple", 4);
items.add("Apple", 4);
// Now you can fetch them by name.
items.get(itemIndices.get("Apple")); // => "Apple"

Of course, you can use a Map<String,Integer> directly, with no need for the List ...