BASIC FILE READING - Reading entire file content

#!/usr/bin/env python3
"""
BASIC FILE READING - Reading entire file content
Demonstrates the most basic way to read a file
"""

import os
import tempfile

print("=" * 60)
print("BASIC FILE READING - Reading Entire File")
print("=" * 60)

# Create a sample file for demonstration
temp_dir = tempfile.gettempdir()
sample_file = os.path.join(temp_dir, "sample_text.txt")

# Write sample content
print("\n1. Creating Sample File")
print("-" * 40)
content = """Hello, this is line 1
This is line 2
And here is line 3
Finally, line 4"""

file_handle = open(sample_file, 'w')
file_handle.write(content)
file_handle.close()
print(f"Created: {sample_file}")

# Method 1: read() - read entire file as single string
print("\n2. Method 1: read() - Entire File as String")
print("-" * 40)
file_handle = open(sample_file, 'r')
full_content = file_handle.read()
file_handle.close()

print("Content:")
print(full_content)
print(f"\nType: {type(full_content)}")
print(f"Length: {len(full_content)} characters")

# Method 2: readlines() - read as list of lines
print("\n3. Method 2: readlines() - List of Lines")
print("-" * 40)
file_handle = open(sample_file, 'r')
lines_list = file_handle.readlines()
file_handle.close()

print(f"Type: {type(lines_list)}")
print(f"Number of lines: {len(lines_list)}")
print("\nLines:")
for i, line in enumerate(lines_list, 1):
    print(f"  Line {i}: {repr(line)}")

# Method 3: readline() - read one line at a time
print("\n4. Method 3: readline() - One Line at Time")
print("-" * 40)
file_handle = open(sample_file, 'r')
print("First line:", repr(file_handle.readline()))
print("Second line:", repr(file_handle.readline()))
print("Third line:", repr(file_handle.readline()))
file_handle.close()

# Cleanup
os.remove(sample_file)
print("\n" + "=" * 60)
print("Key Points:")
print("  - Always close files after opening")
print("  - read() returns entire content as string")
print("  - readlines() returns list of lines")
print("  - readline() reads one line per call")
print("=" * 60)