File Handling

The key function for opening files in Python is open() function. The input parameters are filename and mode.

There are four different modes for opening a file:

• "r" - Read: Opens a file for reading. Returns an error if the file doesn't exist.
• "a" - Append: Opens a file for appending a file. File is created if it doesn't exist.
• "w" - Write: Opens a file for writing. File is created if it doesn't exist.
• "x" - Create: Create a file and write in it. Returns an error if the file exists.

There are two ways a file can be handled:

• "t" - text: Reads a file as a text file.
• "b" - byte: Reads a file as a byte file.

To open a file, use the open() function and specify the method of opening.

If the method is not specified, then read ("r") and text ("t") are taken as default.

Example 1

f = open("file.txt")

Example 2

f = open("file.txt", "rt")

We are so happy that you are here. This is just a test file. To show how file handling in Python works.

The read() method is used to read the file. First, open the file in read ("r") mode.

Example

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

print(f.read())

Output

We are so happy that you are here. This is just a test file. To show how file handling in Python works.

readline() is used to read one line of the file.

Example

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

print(f.readline())

Output

We are so happy that you are here.

If readline() is used 2 times, then the first 2 lines will be read and so on.

Example

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

print(f.readline())

print(f.readline())

Output

We are so happy that you are here.

This is just a test file.

Close the file after reading.

Example

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

print(f.read())

f.close()

Output

We are so happy that you are here. This is just a test file. To show how file handling in Python works.