Reading Text Files

# Basic file reading
# with open("data.txt", "r") as f:
#     content = f.read()        # entire file as string
#     print(content)

# Read lines
# with open("data.txt") as f:
#     lines = f.readlines()     # list of lines
#     for line in lines:
#         print(line.strip())

# Memory-efficient line-by-line
# with open("large_file.txt") as f:
#     for line in f:            # iterator, doesn't load all
#         print(line.strip())

# Demo with io.StringIO (simulates a file)
import io

fake_file = io.StringIO("""Name,Age,City
Alice,25,Mumbai
Bob,30,Delhi
Charlie,28,Bangalore""")

# Read all
content = fake_file.read()
print("Full content:")
print(content)

# Reset position and read lines
fake_file.seek(0)
print("\nLine by line:")
for line in fake_file:
    print(f"  {line.strip()}")

# Read specific number of characters
fake_file.seek(0)
first_20 = fake_file.read(20)
print(f"\nFirst 20 chars: '{first_20}'")