Collections

Rust’s standard library includes a number of very useful data structures called collections. Most other data types represent one specific value, but collections can contain multiple values. Unlike the built-in array and tuple types, the data these collections point to is stored on the heap, which means the amount of data does not need to be known at compile time and can grow or shrink as the program runs.

This exercise will get you familiar with two fundamental data structures that are used very often in Rust programs:

• A vector allows you to store a variable number of values next to each other.
• A hash map allows you to associate a value with a particular key. You may also know this by the names unordered map in C++, dictionary in Python or an associative array in other languages.

Further information

• Storing Lists of Values with Vectors
• Storing Keys with Associated Values in Hash Maps