🧒 Mastering File Handling in Python – The Real-World Way

Python me file handling ek essential skill hai—chahe aap logs store kar rahe ho, configurations read kar rahe ho ya data process kar rahe ho. Har automation ya real-world project kisi na kisi file operation pe depend karta hi hai.

Is guide me hum cover karenge: open(), different file modes, read/write, with-as, common use-cases, real-world tricks, and some next-level tips jo aapko real Python dev banayenge.

🔓 open() – File Handling Ka Gateway

f = open("data.txt", "r")

open() function ka use hota hai kisi file ko access karne ke liye. Ye function do major cheeze leta hai:

• Filename: jise access karna hai
• Mode: read, write, append, etc.

Ye bilkul waise hi hai jaise kisi database se connection establish karna.

🔁 File Modes – Poora Control Aapke Haath Me

Example:

f = open("log.txt", "a")  # append mode

📂 Reading Files – Lines, Entire Text, Selective Access

f = open("data.txt", "r")
content = f.read()
print(content)
f.close()

Alternatives:

• readline() → ek line padhta hai
• readlines() → list of all lines

Tip: Always close file after use using f.close() or better use with-as block.

🌟 with open() – Safe & Clean File Handling

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

with block ensures file properly close ho jaye, even if error aaye.

Real-World Use:

• Logs read karna
• Configuration load karna
• Data parsing

✏️ Writing & Appending Data

with open("log.txt", "w") as f:
    f.write("Starting log...\n")

Append mode:

with open("log.txt", "a") as f:
    f.write("Next log line\n")

Useful for:

• Saving user inputs
• Creating daily logs
• Exporting reports

♻️ Real-World Use Cases

• Chat logs save karna:

with open("chat.txt", "a") as f:
    f.write(f"User: {input()}\n")

• Read config file:

with open("config.ini", "r") as f:
    for line in f:
        if "username" in line:
            print(line)

• CSV file me data save karna:

with open("data.csv", "w") as f:
    f.write("Name,Score\n")
    f.write("Alice,90\n")

🌊 Bonus Tips

• Use os.path.exists("file") to check before accessing
• Use try-except around file ops for safety
• Always handle encoding (utf-8) for non-English data

with open("bio.txt", "r", encoding="utf-8") as f:
    print(f.read())

Aapne ab tak seekha file access, read/write, append, safe handling and real-world use. Next step? In sabka use real projects me karo. Try making:

• Note app (text based)
• Log parser
• CSV export automation

Milte hai agle part mein, Stay tuned, and code smart 🚀