Explore built-in functions

Now that we know how to create our own functions, let's also explore a few of Python's built-in functions.
As we discussed previously, built-in functions are functions that exist within Python and can be called directly.
Our only job is to call them by their name!
And we've already described a few throughout the course; for example, Python's print() and type() functions.
Let's quickly review those two built-in functions before learning about new ones!
First, print() outputs a specified object to the screen.
And then, the type() function returns the data type of its input.
Previously, we've been using functions independently from one another.
For example, we asked Python to print something, or we asked Python to return the data type of something.
As we begin to explore built-in functions, we'll often need to use multiple functions together.
We can do this by passing one function into another as an argument.
For example, in this line of code, Python first returns the data type of "Hello" as a string.
Then, this returned value is passed into the print() function.
This means the data type of string will be printed to the screen.
print() and type() are not the only functions you'll see used together in this way.
In all cases, the general syntax is the same.
The inner function is processed first and then its returned value is passed to the outer function.
Let's consider another aspect of working with built-in functions.
When working with functions, you have to understand what their expected inputs and outputs are.
Some functions only expect specific data types and will return a type error if you use the wrong one.
Other functions need a specific amount of parameters or return a different data type.
The print() function, for example can take in any data type as its input.
It can also take in any number of parameters, even ones with different data types.
Let's explore the input and output of the print() function.
We'll enter three arguments.
The first contains string data.
Then, a comma is used to separate this from the second argument.
This second argument is an integer.
Finally, after another comma, our third argument is another string.
Now, let's run this code.
Perfect!
This printed out just as expected!
The type() function also takes in all data types, but it only accepts one parameter.
Let's explore this input and output too.
Our first line of code will first determine the data type of the word "security" and then pass what it returns into a print() function.
And the second line of code will do the same thing with the value of 73.2.
Now, let's run this and see what happens.
Python first returns output that tells us that the word "security" is string data.
Next, it returns another line of output that tells us that 73.2 is float data.
Now, we know what to consider before using a built-in function.
We have to know exactly how many parameters it requires and what data types they can be.
We also need to know what kind of output it produces.
Let's learn a couple of new built-in functions and think about this.
We'll start with max().
The max() function returns the largest numeric input passed into it.
It doesn't have a defined number of parameters that it accepts.
Let's explore the max() function.
We'll pass three arguments into max() in the form of variables.
So let's first define those variables.
We'll set the value of a to 3, b to 9, and c to 6.
Then, we'll pass these variables into the max() function and print them.
Let's run this.
It tells us the highest value among those is 9.
Now, let's study one more built-in function: the sorted() function.
The sorted() function sorts the components of a list.
This function can be very useful in a security setting.
When working with lists, we often have to sort them.
With lists of numbers, we sort them from smallest to largest or the other way around.
With lists of string data, we might need to sort them alphabetically.
Imagine you have a list that contains usernames in your organization and you wanted to sort them alphabetically.
Let's use Python's sorted() function for this.
We'll specify our list through a variable named usernames.
In this list, we'll include all of the usernames we want to sort.
Now, we'll use the sorted() function to sort these names by passing the usernames variable into it.
And then we'll pass its output into the print statement so it can be displayed on the screen.
When we run it, everything is now in order!
These are just a few of the built-in functions available for your use.
As you work more in Python, you'll become familiar with others that can help you in your programs.