Lesson 06: Python built in functions - CodeAcademy-Online/python-level-1 GitHub Wiki

🐍 Built-in functions

`print()`

As we have seen before, we used print couple of times already and made ourselves familiar with it. We did not create the function itself as it comes out of the box right after installing python. It is important to mention that this function is not as dull as it may seem from the first glance, in fact it's quite versatile:

print(object(s), sep=separator, end=end, file=file, flush=flush)

argument	meaning
object(s)	Any object, and as many as you like. Will be converted to string before printed
sep='separator'	Optional. Specify how to separate the objects, if there is more than one. Default is ' '
end='end'	Optional. Specify what to print at the end. Default is '\n' (line feed)
file	Optional. An object with a write method. Default is sys.stdout
flush	Optional. A Boolean, specifying if the output is flushed (True) or buffered (False). Default is False

Some examples:

# Simple print
print("hello world")

# Gets the same result but slightly different:
print("hello", "world")

# Gets the same result but is even more different:
print(*["hello", "world"])

# let's play with separator:
print("hello world", sep=",")

# some more
print("hello", "world", sep=" amazing ")

`type()`

Another useful function for us to understand what we are dealing with in python is type. Often it helps us to understand what is the type of instance of the object are we dealing with:

Examples:

greet = "Hello World"
print(type(a))

number = 2022
print(type(number))

my_list = [1, 2, 3]
print(type(my_list))

print(type(my_list[0]))

This becomes really helpful later dealing with more complex programs.

`len()`

We have already seen this function before with list. As you remember it does return the length of the list or tuple as for example. Nevertheless it still works with strings as well.

Examples:

word = "something"
length = len(word)

print(f"length of the word {word} is: {length}")

my_list = [1, 2, 3]

print(f"length of the list {my_list} is: {len(my_list)}")

`round()`

Function allows to round float to a certain decimal point:

round(number, ndigits=None)

argument	meaning
number	number that needs to be rounded
ndigits	decimal places, by default None, meaning that it will be rounded to integer value

Examples:

print(round(1.999))

print(round(1.5555, 2))

`sorted()`

What if we would like to sort values in the list or tuple

sorted(iterable, key=None, reverse=False)

argument	meaning
iterable	A sequence (string, tuple, list) or collection (set, dictionary, frozen set) or any other iterator.
reverse	(Optional) - If True, the sorted list is reversed (or sorted in descending order). Defaults to False if not provided.
key	(Optional) - A function that serves as a key for the sort comparison. Defaults to None.

Examples:

my_list = [45, 20, 14, 55]
sorted_list = sorted(my_list)

print(sorted_list)

sorted_reverse_list = sorted(my_list, reverse=True)

print(sorted_reverse_list)

What about string values?

my_list = ["Albert", "Nicola", "Thomas"]
sorted_list = sorted(my_list)

print(sorted_list)

sorted_reverse_list = sorted(my_list, reverse=True)

print(sorted_reverse_list)

Still works!

There are plenty more built-in functions to explore at link Some of them are yet too early for us but as we progress throughout the course we will be using more and more of them.

🧠 Exercises:

Create a list of different types of python objects, and print all the types.
Print all the items (from previous) separated with "|"
Create a list of floats with 3 decimal points, create another list with all the values rounded to 2 decimals.
Create a list with student names and sort them, print the result to the terminal.
Write a program that allows user to write in any float number and then round it.

🌐 Extra reading:

Built in methods