Working with Files

File Handling Concepts Table

SI	Section	Usage Scenario	Pros	Cons
1	with open() for file handling	Reading/writing files safely, ensuring proper closure	Automatically closes files Cleaner code Less prone to errors	Limited to scope of with block
2	File Modes ('r', 'w', 'a')	Choose based on whether you're reading, writing, or appending	Flexible modes Supports text and binary modes 'r+' allows read/write	'w' can overwrite data Wrong mode may raise error
3	Reading large files efficiently	Log files, datasets – when full file can’t be loaded into memory	Memory efficient Great for huge files	Slightly more logic needed
4	File Reading Techniques	Different ways of reading based on need (whole, lines, line by line)	Multiple options for use cases readlines() useful for processing all at once	read() and readlines() can be memory-heavy for big files
5	Context Managers	Safe file and resource handling using with	Auto resource management Prevents file leaks Readable and Pythonic	Can't use file object after exiting with block

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Code Sample

with open()

with open('example.txt', 'r') as file:
    data = file.read()
    print(data)

Read or write

# Reading a file
with open('example.txt', 'r') as file:
    content = file.read()

# Writing to a file
with open('output.txt', 'w') as file:
    file.write("Hello, World!")

Reading Large Files Efficiently (Line by Line)

with open('large_file.txt', 'r') as file:
    for line in file:
        print(line.strip())

File Reading Techniques

# Read the entire file
with open('example.txt', 'r') as file:
    content = file.read()

# Read all lines into a list
with open('example.txt', 'r') as file:
    lines = file.readlines()

# Read one line
with open('example.txt', 'r') as file:
    line = file.readline()

Context Manager

with open('example.txt', 'r') as file:
    content = file.read()
# File automatically closed after block