Here is a clear, complete, and exam-oriented explanation of the read() and write() methods in Python file handling

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⭐ read() and write() Methods in Python

In Python, file handling is performed using built-in functions, and two of the most commonly used methods are:

• read() → used to read data from a file
• write() → used to write data into a file

These methods work only when the file is opened in appropriate mode.

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⭐ 1. read() Method

The read() method reads data from a file.
You can read the entire file or a specific number of characters.

✔ Syntax

file_object.read(size)

Parameters

• size (optional): number of characters/bytes to read
  • If size is not given, it reads the entire file.

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✔ Example 1: Read entire file

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

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✔ Example 2: Read first N characters

f = open("data.txt", "r")
print(f.read(10))  # reads first 10 characters
f.close()

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✔ Example 3: Read file in parts (useful for large files)

f = open("data.txt", "r")
print(f.read(5))   # first 5 chars
print(f.read(5))   # next 5 chars
f.close()

💡 Each call to read() moves the file pointer forward.

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✔ Example 4: Handling empty file or end of file (EOF)

data = f.read()
if data == "":
    print("Reached end of file")

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⭐ 2. write() Method

The write() method writes a string to a file.

✔ Syntax

file_object.write(string)

Important Notes

• Only string data can be written in text mode
• In write mode "w", file gets overwritten
• In append mode "a", new data goes to end of file
• write() returns → number of characters written

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✔ Example 1: Writing to a file

f = open("data.txt", "w")
f.write("Hello Python!\n")
f.write("This is file handling.")
f.close()

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✔ Example 2: Appending to a file

f = open("data.txt", "a")
f.write("\nThis line is added later.")
f.close()

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✔ Example 3: Checking number of characters written

f = open("output.txt", "w")
count = f.write("Python is amazing!")
print("Characters written:", count)
f.close()

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⭐ Difference Between read() and write()

Feature	read()	write()
Purpose	Reads data from file	Writes data to file
Modes allowed	"r", "r+", "a+", "w+"	"w", "a", "r+", "w+", "a+"
Return value	Content of file	Number of characters written
Moves file pointer	Yes	Yes
Data type	Returns string	Accepts string

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⭐ Best Practice: Use with Block

with open("data.txt", "w") as f:
    f.write("Hello Students!")

✔ File closes automatically
✔ Prevents data loss

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⭐ Exam-Ready Short Answer

The read() method is used to read data from a file. It can read the entire file or a specified number of characters.
The write() method is used to write data into a file and returns the number of characters written. Both methods work on file objects created using the open() function and move the file pointer accordingly.

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