Working with strings
Working with strings in Solidity is not as easy as working with strings in other high-level programming languages, such as JavaScript, Python, and so on. Therefore, many Solidity programmers have come up with various libraries and contracts to make it easy to work with strings.
The strings library is the most popular strings utility library. It lets us join, concatenate, split, compare, and so on by converting a string to something called a slice. A slice is a struct that holds the length of the string and the address of the string. Since a slice only has to specify an offset and a length, copying and manipulating slices is a lot less expensive than copying and manipulating the strings they reference.
To further reduce gas costs, most functions on slice that need to return a slice modify the original one instead of allocating a new one; for instance, s.split(".") will return the text up to the first ".", modifying s to only contain the remainder of the string after the...
