diff --git a/docs/python-tutorial/chapters/04-built-in-functions-pt-1.md b/docs/python-tutorial/chapters/04-built-in-functions-pt-1.md new file mode 100644 index 0000000..22578d3 --- /dev/null +++ b/docs/python-tutorial/chapters/04-built-in-functions-pt-1.md @@ -0,0 +1,113 @@ +--- +description: Built-in Functions Part 1 +--- + +# Built-in Functions Part 1 + +!!! note + + This chapter will only cover how to use some built-in functions. So, for now, consider functions as + helper code which does some specific task and is pre-written for you to use. You will learn about + functions in great detail later in this tutorial, so don't worry about that for now. + +Python has many built-in functions which you can use to make your life easier. In this section, we +will take a look at `print`, `input` and some type-casting functions in detail. + +## `print()` + +The `print` function is used to print/show something on the screen (also known as the terminal or +standard output). With this, you can write the first program that every programmer writes when they +learn a new language: + +```python +print("Hello World!") # Output: Hello World! +``` + +This line of code will print `Hello World!` on your screen. You can also print any other data type +(such as `int`, `float`, or `bool`) using `print`. + +```python +print("My name is Alex") # Output: My name is Alex +print(56) # Output: 56 +print(3.14) # Output: 3.14 +print(False) # Output: False +``` + +You can also print the data currently present in a variable using `print`. + +```python +a = 5 +print(a) # Output: 5 +a = "python" +print(a) # Output: python +``` + +Each `print` statement prints on a new line. You can print multiple things using a single `print` +statement by separating them using commas (`,`), which will result in all the values being printed +on the same line separated by spaces. + +```python +print("Value of pi is", 3.14) # Output: Value of pi is 3.14 +``` + +!!! note + + Keep in mind that this works only in `print` and CANNOT be used to combine different strings or + variables with strings otherwise. + +## `input()` + +The `input` function is used to take input from the user through the terminal (also known as the +standard input). It returns everything the user types until the user hits the `Enter`/ `Return` key +on the keyboard. You can also give a `str` to the `input` function which will be displayed on the +screen while taking the input. For example: + +```python +input("Enter your name: ") +``` + +The above code will print `Enter your name: ` followed by a blinking cursor where you can type the +actual input. Now, to actually use the value the user entered, you need to assign the value returned +by the `input` function to a variable. + +```python +name = input("Enter your name: ") +print(name) +``` + +The `input` function returns the input as a `str`, so the variable `name` will be of type `str`. The +output of above code will be whatever the user entered. + +## Type Casting + +Now you know how to take input from the user, but, the `input` function returns a `str` no matter +what the user types. So, for example, if the user types `54`, it will return a `str` (`"54"`), not +an `int` (`54`). So, if you want to use the number the user entered, you will need to convert the +`str` returned by `input` to an `int`. This process of converting one data type to another is called +**type casting**. + +There are two types of type casting: + +1. **Implicit Type Casting**: It is done automatically by Python when it is needed. +2. **Explicit Type Casting**: It is done manually by the programmer. + +### Explicit Type Casting + +Python has many built-in functions for explicit type casting, and they are named the same as the +data type they cast to. Here is the list of type-casting functions with the type they cast to: + +| Function | Type | +|-----------|------| +| `bool()` | `bool` | +| `float()` | `float` | +| `int()` | `int` | +| `str()` | `str` | + +For example, you can do this to get a number from the user: + +```python +number_string = input("Enter a number: ") +number_int = int(number_string) +``` + +Similarly, you can use other functions according to the data type you need. diff --git a/docs/python-tutorial/chapters/index.md b/docs/python-tutorial/chapters/index.md index 8c143b6..e30f2eb 100644 --- a/docs/python-tutorial/chapters/index.md +++ b/docs/python-tutorial/chapters/index.md @@ -12,7 +12,7 @@ in-depth Python features. - [Brief Python History](01-python-history.md) - [Introduction to Variables](02-intro-to-variables.md) - [Data Types pt 1 (`string`, `int`, `float` & `bool`)](03-data-types-pt01.md) -- Builtin Functions pt 1 (`print` & `input` and type casting) +- [Builtin Functions pt 1 (`print` & `input` and type casting)](04-built-in-functions-pt-1.md) - String Interpolation & Concatenation (f-strings, str.format & +) - Operators pt 1 (Comparison & Arithmetic) - Conditional Statements (`if`, `else` & `elif`) diff --git a/zensical.toml b/zensical.toml index c2df958..0f9db82 100644 --- a/zensical.toml +++ b/zensical.toml @@ -24,6 +24,7 @@ nav = [ "python-tutorial/chapters/01-python-history.md", "python-tutorial/chapters/02-intro-to-variables.md", "python-tutorial/chapters/03-data-types-pt01.md", + "python-tutorial/chapters/04-built-in-functions-pt-1.md", ] }, { "Resources" = [ "resources/index.md",