What is the principle of immutability of string data in programming?

In programming, the principle of immutability of string data means that once a string is created, it cannot be changed. Any operation that appears to modify the string (for example, adding a character or replacing part of the string) actually creates a new string in memory, while the original remains unchanged.

In Go, strings are immutable: if you need to modify a string, a new string with the desired changes is created. This enhances safety and simplifies working with concurrent processes, as immutable objects do not require synchronization.

Example:

s := "hello"
s2 := s + " world" // creates a new string "hello world"
// s remains "hello"

Thus, string immutability helps avoid unexpected side effects when working with data.