The tell() method in Python is a built-in method used to get the current file position within a file. It returns the current position of the file pointer, which indicates the next position that will be read or written. The position is measured in bytes from the beginning of the file.
Syntax
file.tell()
Return Value
The tell() method returns the current position of the file pointer in bytes from the beginning of the file.
Examples
Example 1: Get the current file position
In this example, we will use the tell() method to get the current position of the file pointer:
file = open("example.txt", "r")
print(file.tell())
file.close()
In this example, we opened a file “example.txt” in read mode and used the tell() method to get the current position of the file pointer. The file pointer is at the beginning of the file, so the output will be 0.
Output:
0
Example 2: Get the current file position after reading data
In this example, we will use the tell() method to get the current position of the file pointer after reading data from a file:
file = open("example.txt", "r")
print(file.read(5))
print(file.tell())
file.close()
In this example, we opened a file “example.txt” in read mode, read the first 5 characters from the file using the read() method, and used the tell() method to get the current position of the file pointer. The file pointer has moved 5 bytes from the beginning of the file, so the output will be 5.
Output:
Hello 5
Example 3: Get the current file position after writing data
In this example, we will use the tell() method to get the current position of the file pointer after writing data to a file:
file = open("example.txt", "w")
file.write("Hello, World!")
print(file.tell())
file.close()
In this example, we opened a file “example.txt” in write mode, wrote the string “Hello, World!” to the file using the write() method, and used the tell() method to get the current position of the file pointer. The file pointer has moved to the end of the file after writing, so the output will be the length of the string “Hello, World!” in bytes.
Output:
13
Use Cases
- The
tell()method can be used to get the current position of the file pointer before and after reading or writing data to a file. - The
tell()method can be used to determine the size of a file by getting the current position of the file pointer and subtracting it from the end of the file. - The
tell()method can be used to keep track of the current position of the file pointer while iterating through a file line by line using a loop.
Conclusion
The tell() method in Python is a useful method for getting the current position of the file pointer within a file. It can be used to keep track of the position while reading or writing data to a file, and can also be used to determine the size of a file. By understanding how to use the tell() method, you can more effectively manipulate and work with files in your Python programs.
