readme.md

➡️ Day 7: Reading From and Writing to Files

Day 7 gave our programs a memory! We learned about File I/O (Input/Output), which allows our programs to save data to files and read it back later. This is how applications remember information even after they are closed.

• Cheat Sheet: day_7_cheatsheet.md

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⭐ Key Concepts Covered:

• The with open() Statement: The standard, safe way to open and automatically close files.
• File Modes: Understanding the difference between 'r' (read), 'w' (write, which erases), and 'a' (append).
• Reading Files: Using .read(), .readlines(), and looping line-by-line.
• Writing Files: Using .write() to save strings to a file.
• The os Module: Using os.path.exists() to safely check if a file exists before trying to open it.

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💡 Highlight Snippet:

# A safe way to append a new high score to a file
new_score = "Player 1: 500\n"

# 'a' mode creates the file if it doesn't exist, or adds to the end if it does.
with open('scores.txt', 'a') as file:
    file.write(new_score)

print("Score saved successfully!")