> Source URL: /resources/variables.resource
# Variables

## What It Is

A variable is a named container that stores a value. You can think of it like a labeled box — you put something inside, and later you can use the label to get it back.

## Why We Use It

Variables let you:

- **Store data** so you can use it later
- **Reuse values** without typing them over and over
- **Update information** in one place instead of many
- **Give meaning** to your data with descriptive names

In sports analytics, variables might hold a player's name, their point total, a team's win percentage, or any other piece of data
you want to work with.

---

## How to Use It

### Basic Syntax

```python
variable_name = value
```

The `=` sign means "assign" — you're putting the value into the variable. Think of it like writing a label on a box and putting something inside.

### Examples with Sports Data

```python
# Storing text (strings) - use quotes
player_name = "Wilt Chamberlain"
team = "Philadelphia Warriors"
date = "March 2, 1962"

# Storing numbers - no quotes needed
points_scored = 100
field_goals = 36
free_throws = 28
games_played = 1

# You can use the variables later
print(player_name)  # Output: Wilt Chamberlain
print(points_scored)  # Output: 100
```

### Updating Variables

Variables can change — that's why they're called "variables"! You can update them anytime by assigning a new value.

```python
score = 0
print(score)  # Output: 0

score = 50
print(score)  # Output: 50

score = 100
print(score)  # Output: 100
```

---

## Naming Rules

Python has rules for variable names:

| Rule                               | Good Example                                | Bad Example    |
| ---------------------------------- | ------------------------------------------- | -------------- |
| Start with a letter or underscore  | `player_name`                               | `1st_player`   |
| No spaces                          | `total_points`                              | `total points` |
| Only letters, numbers, underscores | `stat_2024`                                 | `stat-2024`    |
| Case sensitive                     | `Score` and `score` are different variables |

While these rules have no effect on the functionality of your code, it is good practice to follow them.

### Naming Tips

Choose names that describe what the variable holds. Good names make your code easier to read and understand:

```python
# Good - descriptive names
player_name = "LeBron James"
career_points = 40000
championship_rings = 4

# Bad - unclear names
x = "LeBron James"
n = 40000
thing = 4
```

---

## Two Types of Values

Python treats text and numbers differently. It's important to know which one you're using!

### Strings (Text)

Text values go inside quotes — single `'` or double `"` both work:

```python
player = "Tom Brady"
team = 'New England Patriots'
nickname = "The GOAT"
```

### Numbers

Numbers are written without quotes:

```python
# Integers (whole numbers)
touchdowns = 649
super_bowls = 7
age = 45

# Decimals
completion_rate = 64.2
yards_per_attempt = 7.5
```

**Important:** `"100"` (in quotes) is text, but `100` (no quotes) is a number. They're different! You can't do math with text that looks like a number.

```python
text_number = "100"
real_number = 100

# This would cause an error:
# result = text_number + 50  # Can't add text and numbers!

# This works:
result = real_number + 50  # Result is 150
```

---

## Common Pitfalls

| Problem                                   | What Went Wrong                          | Fix                                   |
| ----------------------------------------- | ---------------------------------------- | ------------------------------------- |
| `NameError: name 'player' is not defined` | Variable doesn't exist yet               | Create the variable before using it   |
| `SyntaxError` with variable name          | Used a space or started with a number    | Follow naming rules                   |
| Number math not working                   | Number is actually a string (in quotes)  | Remove the quotes                     |
| Wrong value showing                       | You might have updated it somewhere else | Check all places the variable is used |

---

## Quick Reference

```python
# Creating variables
player = "Shohei Ohtani"
home_runs = 44
batting_average = 0.304

# Using variables
print(player)
print(home_runs)

# Updating variables
home_runs = 45  # He hit another one!
```


---

## Backlinks

The following sources link to this document:

- [Variables](/resources/index.resources.llm.md)
- [Variables](/users/annie-h/week-5.path.llm.md)
- [Variables](/users/charlie-m/week-5.path.llm.md)
- [Variables](/users/emily-kate-s/week-5.path.llm.md)
- [Variables](/users/josiah-c/week-5.path.llm.md)
- [Variables](/users/john-p/week-5.path.llm.md)
- [Variables](/users/jake-f/week-5.path.llm.md)
- [Variables](/users/elizabeth-b/week-5.path.llm.md)