# Basic file operations
file = open("example.txt", "r")  # Open for reading
content = file.read()
file.close()  # Always close!

# Better: use context manager (auto-closes)
with open("example.txt", "r") as file:
    content = file.read()
# File is automatically closed here

# Write mode (creates or overwrites)
with open("output.txt", "w") as f:
    f.write("Hello, World!\n")

# Append mode (adds to end)
with open("output.txt", "a") as f:
    f.write("Another line\n")

# Read mode
with open("output.txt", "r") as f:
    print(f.read())
# Hello, World!
# Another line

with open("data.txt", "r") as f:
    content = f.read()
    print(content)

# readline() - one line at a time
with open("data.txt", "r") as f:
    line1 = f.readline()  # First line
    line2 = f.readline()  # Second line

# readlines() - all lines as list
with open("data.txt", "r") as f:
    lines = f.readlines()
    for line in lines:
        print(line.strip())

# Iterate directly (most memory-efficient)
with open("data.txt", "r") as f:
    for line in f:
        print(line.strip())

# Specify encoding (important for non-ASCII text)
with open("data.txt", "r", encoding="utf-8") as f:
    content = f.read()

# Write a string
with open("output.txt", "w") as f:
    f.write("Line 1\n")
    f.write("Line 2\n")

# Write multiple lines
lines = ["Python\n", "is\n", "awesome\n"]
with open("output.txt", "w") as f:
    f.writelines(lines)

# Write with print
with open("output.txt", "w") as f:
    print("Hello, World!", file=f)
    print("Python is great!", file=f)

# Formatted writing
students = [("Alice", 90), ("Bob", 85), ("Charlie", 92)]
with open("grades.txt", "w") as f:
    f.write("Name        Grade\n")
    f.write("-" * 20 + "\n")
    for name, grade in students:
        f.write(f"{name:<12}{grade}\n")

import csv

# Writing CSV
students = [
    ["Name", "Age", "Grade"],
    ["Alice", 25, "A"],
    ["Bob", 22, "B"],
    ["Charlie", 28, "A"],
]

with open("students.csv", "w", newline="") as f:
    writer = csv.writer(f)
    writer.writerows(students)

# Reading CSV
with open("students.csv", "r") as f:
    reader = csv.reader(f)
    header = next(reader)  # Skip header
    for row in reader:
        print(f"{row[0]}: Age {row[1]}, Grade {row[2]}")

# Using DictReader/DictWriter
with open("students.csv", "r") as f:
    reader = csv.DictReader(f)
    for row in reader:
        print(f"{row['Name']} got {row['Grade']}")

import json

# Write JSON
data = {
    "name": "Alice",
    "age": 30,
    "skills": ["Python", "SQL", "ML"],
    "address": {
        "city": "New York",
        "state": "NY"
    }
}

with open("data.json", "w") as f:
    json.dump(data, f, indent=2)

# Read JSON
with open("data.json", "r") as f:
    loaded = json.load(f)
    print(loaded["name"])       # Alice
    print(loaded["skills"][0])  # Python

# JSON string conversion
json_string = json.dumps(data, indent=2)
print(json_string)

data_back = json.loads(json_string)

import os
import shutil
from pathlib import Path

# Check file existence
print(os.path.exists("data.txt"))    # True/False
print(os.path.isfile("data.txt"))    # True if file
print(os.path.isdir("data"))         # True if directory

# File information
print(os.path.getsize("data.txt"))   # Size in bytes
print(os.path.basename("/path/to/file.txt"))  # file.txt
print(os.path.dirname("/path/to/file.txt"))   # /path/to

# Create directories
os.makedirs("path/to/dir", exist_ok=True)

# Rename/move
os.rename("old.txt", "new.txt")

# Delete
os.remove("file.txt")          # Delete file
os.rmdir("empty_dir")          # Delete empty directory
shutil.rmtree("dir_with_files") # Delete directory and contents

# List directory contents
for item in os.listdir("."):
    print(item)

# Using pathlib (modern approach)
p = Path("data")
p.mkdir(parents=True, exist_ok=True)

for file in Path(".").glob("*.txt"):
    print(f"{file.name}: {file.stat().st_size} bytes")

from pathlib import Path

# Create paths
home = Path.home()
project = Path("project")
config = project / "config" / "settings.json"

print(config)           # project/config/settings.json
print(config.parent)    # project/config
print(config.name)      # settings.json
print(config.stem)      # settings
print(config.suffix)    # .json

# Read and write with pathlib
p = Path("example.txt")
p.write_text("Hello, World!")
content = p.read_text()
print(content)  # Hello, World!

# Binary read/write
p.write_bytes(b"binary data")
data = p.read_bytes()

# Check existence
if p.exists():
    print(f"Size: {p.stat().st_size} bytes")

# Iterate directory
for item in Path(".").iterdir():
    if item.is_file():
        print(f"File: {item.name}")
    elif item.is_dir():
        print(f"Dir:  {item.name}/")

# Glob patterns
for py_file in Path(".").rglob("*.py"):
    print(py_file)

# Handle file errors gracefully
try:
    with open("missing_file.txt", "r") as f:
        content = f.read()
except FileNotFoundError:
    print("File not found!")
except PermissionError:
    print("Permission denied!")
except IOError as e:
    print(f"IO error: {e}")

"""
Analyze a log file and generate a summary.
"""

from pathlib import Path
from collections import Counter
from datetime import datetime

def analyze_log(log_path):
    """Analyze a log file and return statistics."""
    levels = Counter()
    errors = []
    line_count = 0

    path = Path(log_path)
    if not path.exists():
        print(f"Log file not found: {log_path}")
        return

    with open(path, "r", encoding="utf-8") as f:
        for line in f:
            line_count += 1
            line = line.strip()

            # Count log levels
            for level in ["ERROR", "WARNING", "INFO", "DEBUG"]:
                if level in line:
                    levels[level] += 1
                    if level == "ERROR":
                        errors.append(line)
                    break

    # Generate report
    report = f"""
Log Analysis Report
{'=' * 40}
File: {log_path}
Total lines: {line_count}
Generated: {datetime.now().strftime('%Y-%m-%d %H:%M')}

Log Level Summary:
"""
    for level, count in levels.most_common():
        bar = "█" * (count * 2)
        report += f"  {level:<10} {count:>5}  {bar}\n"

    if errors:
        report += f"\nErrors ({len(errors)}):\n"
        for error in errors[:5]:
            report += f"  • {error[:80]}\n"

    return report