In this project you will read weather data from a file and populate a Java ArrayList with the file data. The data is then uniquified in a Set data structure and stored in a HashMap for accessing data by year.

Java's collections framework contains data structures that are built for efficiency. They are used to store and retrieve data in various formats. A list such as an ArrayList can be used in place of an array to contain data where the size cannot be determined ahead of time. A LinkeList is like an ArrayList, except elements can be more quickly added and deleted from it, since no shifting needs to occur. A Hashmap is used to quickly look up a value based on a key rather than a numerical index, for example, to look up a phone number based on a key containing a person's name. A Set may be used to remove duplicates from a list, simply by assigning the data to it. Note: This course works best for learners who are based in the North America region. We’re currently working on providing the same experience in other regions.