Python Data Structures and Algorithms

Symbol tables

Symbol tables are used by compilers and interpreters to keep track of the symbols that have been declared and information about them. Symbol tables are often built using hash tables, since it is important to efficiently retrieve a symbol in the table.

Let us look at an example. Suppose we have the following Python code:

    name = "Joe"     age = 27 

Here we have two symbols, name and age. They belong to a namespace, which could be __main__, but it could also be the name of a module if you placed it there. Each symbol has a value; name has the value Joe and age has the value 27. A symbol table allows the compiler or the interpreter to look these values up. The symbols name and age become the keys in our hash table. All the other information ...