How Python Interpreter Works

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Can you tell me how Python interpreter works?

Python's interpreter essentially eliminates the need for a compiler by interpreting the code at run time.

That's why it does not have a compiler, since the interpreter replaces it. But how does it work?

Variables point to a value at runtime, and the interpreter uses their value at runtime based on their type.

How do you declare the variable type?

You do not have to declare variables with Python's interpreter, though the language does have standard variable types like integer.

Glad to know something about it is standard.

Python determines the type of every variable and its value at runtime, though that could change each time you run it.

That does not sound too reliable.

One of the benefits of the Python interpreter is your ability to type code directly into it.

How is that a benefit?

The interpreter can test that code right then, speeding up testing and diagnosis.
Reading a variable that doesn't have a value the interpreter can figure out results in a runtime error.

Because you are running it immediately, instead of waiting for compiling, you find those bugs faster.

Yes. Python's interpreter looks at the types present in each code module as it is run.

Then you find the bugs in the code.

Python does not generate code at runtime, even with the interpreter.

But re-interpreting it each time will probably slow it down.

The Python interpreter is slower than C++, but it also makes the code more flexible. And you do not have to compile it to run it, meaning you can run it immediately.

I remember the XKCD joke about programmers always having the excuse that they are not wasting time, they are waiting on the compiling.

And that's not a waste. Python's garbage collector automatically allocates and de-allocates memory as the interpreter runs, avoiding some of the problems compiled code can come up with.

That's probably why I've never run into a Python error, but tons of Java errors.