Writing files in the background in Python

In this tutorial, we will learn about the multi-threading in Python. It helps us to perform multiple tasks at a time. Python has a module called threading for multitasking.

We see how it works by writing data to a file in the background while calculating the sum of elements in a list. Let's see the steps involved in the program.

• Import the threading module.

• Create a class by inheriting threading.Thread class.

• Write the file code inside the run method in the above class.

• Initialize the required data.

• Write the code to calculate the sum of numbers in a list.

Example

# importing the modules
import threading
# creating a class by inhering the threading.Thread base class
class MultiTask(threading.Thread):
   def __init__(self, message, filename):
      # invoking the Base class
      threading.Thread.__init__(self)
      # initializing the variables to class
      self.message = message
      self.filename = filename
   # run method that invokes in background
   def run(self):
      # opening the file in write mode
      with open(filename, 'w+') as file:
         file.write(message)
      print("Finished writing to a file in background")
# initial code
if __name__ == '__main__':
   # initializing the variables
   message = "We're from Tutorialspoint"
   filename = "tutorialspoint.txt"
   # instantiation of the above class for background writing
   file_write = MultiTask(message, filename)
   # starting the task in background
   file_write.start()
   # another task
   print("It will run parallelly to the above task")
   nums = [1, 2, 3, 4, 5]
   print(f"Sum of numbers 1-5: {sum(nums)}")
   # completing the background task
   file_write.join()

It will run parallelly to the above task

Sum of numbers 1-5: 15

Finished writing to a file in background

Output

You can check the directory for the file. If you run the above code, you will get the following output.

It will run parallelly to the above task
Sum of numbers 1-5: 15
Finished writing to a file in background

Conclusion

If you have any queries from the tutorial, mention them in the comment section.

Hafeezul Kareem

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Updated on: 12-Feb-2020

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