## Python Basics
### Comments
Comments are lines of code that aren't compiled nor executed when the program runs. They're used as a way to annotate the source code to provide explanations on how areas of the code work.
#### Single-Line Comments
Single-Line comments are written using a hash symbol (`#`) prefix.
```python
# This is a single-line comment.
```
#### Multi-Line Comments
Multi-Line comments are written using triple single ( `'''`) or triple double quotes (`"""`).
```python
'''This is a
multi-line comment.'''
```
### Expressions
A Python expression consists of values and operators that evaluate down to a single value.
### Math Operators
| Operator | Description |
| --- | --- |
| `**` | Exponent |
| `//` | Integer Division |
| `%` | Modulus/Remainder |
| `*` | Multiplication |
| `/` | Division |
| `+` | Addition |
| `-` | Subtraction |
### Order of Operations
Python follows the mathematical order of operations which can be summarized using the acronym PEMDAS (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction).
### Data Types
| Data Type | Example |
| ------------------------------ | ---------------- |
| Integers (int) | -1, 0, 1, 2 |
| Floating-Point Numbers (float) | -1.25, 0.5, 1.75 |
| Strings | 'Hello, World!' |
### Type Conversion
`str()` is used to convert a value to the string type.
`int()` converts a value to the integer type.
`float()` converts a value to the floating-point type.
```python
str(42) # "42"
int("42") # 42
float("42") # 42.0
```
### Variables
Variables are a way of storing data. A variable is initialized the first time a value is stored in it.
Variables are initialized using an assignment statement, which uses a single equals sign.
```python
spam = 'Hello, World!'
```
Variable can be used in expressions.
A variable can be overwritten, by storing a new value.
The following rules must be followed when declaring variable names:
1) Use only one word, with no spaces.
2) Only use letters, numbers, and underscores.
3) Variable name can't begin with a number