If you want to get started with using Blueprint Map containers in UE4, please refer to the following property list.Īll keys in a Map must be defined (initialized).Ĭurrently, only single key-value pairs are supported in Blueprint Maps.Īdding, removing, and finding values, using their associated keys in a Map, are fast operations.Ĭurrently, Map values are immutable, which means that they cannot be modified after they have been created.Īlthough key-types may differ from value-types, all keys and values in a Map are homogeneous (of the same type).

With the aforementioned warning in mind, go ahead and name the fourth key Date, setting its value to 2.Įxcellent work! You've just created a new Blueprint Map, having added and edited four key-value pairs. Although duplicate values are allowed, you cannot have duplicate keys. Unreal Editor will emit a warning if you try to add a duplicate key into a Blueprint Map. You'll also learn about the properties of Maps, which are being included to help you get the most out of using Maps in your game projects. Having the ability to associate items in a container with their respective keys, enables developers to efficiently lookup and retrieve items with the use of the keys, and so harness Maps in creative ways.Īs you read through this page, you'll learn how to create and edit Blueprint Maps. When using Arrays, the label is the item's sequential index in the container, whereas, when using Maps, the label is a key that's associated with the item in the container. Maps are similar to Arrays in that they both use a label to indicate where the item is located in the container, however, labels for Maps are different from those used for Arrays. For example, when using Arrays to store items for later use, the item's label is its place in the array.

If you've used Arrays to store and work with collections of items, you've already started using Blueprint containers in UE4. If you're unfamiliar with the term 'container' think of a storage box, where you label items and place them inside of the box for immediate (or later) use. Much like Arrays and Sets, Blueprint Maps have a variety of uses when developing a game. The Blueprint Application Programming Interface (API) in Unreal Engine 4 (UE4) has a Map container type.

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