The print() function
The only argument delivered to the print() function in this example is a string:
print("Hello, World!")
As you can see, the string is delimited with quotes - in fact, the quotes make the string - they cut out a part of the code and assign a different meaning to it.
You can imagine that the quotes say something like: the text between us is not code It isn't intended to be executed, and you should take it as is.
Almost anything you put inside the quotes will be take literally, not as code but as data. Try to play with this particular string, - modify it, enter some new content, delete some of the existing content.
There's more than one way to specify a string inside Python's code, but for now, though, this one is enough.
So far, you have learned about two important parts of the code: the function and the string. We've talked about them in terms of syntax, but now it's time to discuss them in terms of semantics.
The print() function
The function name (print in this case) along with the parentheses and argument(s), forms the function invocation.
We'll discuss this in more depth soon, but we should just shed a little light on it right now.
print("Hello, World!")
What happens when Python encounters an invocation like this one below?
function_name(argument)
Let's see:
- First, Python Checks if the name specified is legal (it browses its internal data in order to find an existing function of the name; if this search fails, Python aborts the code)
- Second, Python checks if the function's requirements for the number of arguments allows you to invoke the function in this way (e.g., if a specific function demands exactly two arguments, any invocation delivering only one argument will be considered erroneous, and will abort the code's execution)
- Third, Python leaves your coe for a moment and jumps into the function you want to invoke; of course, it takes your argument(s) too and passes it/them to the function;
- Fourth, the function executes its code, causes the desired effect (if any), evaluates the desired result(s) (if any) and finishes its task
- Finally, Python returns to your code (to the place just after the invocation) and resumes its execution
