In the first line of our newly modified program, you should see that we are now importing the threading module; this will enable us to create our first multithreaded application. We then abstract our filename generation, and call the downloadImage function into our own executeThread function.
Within the main function, we first create an empty array of threads, and then iterate 10 times, creating a new thread object, appending this to our array of threads, and then starting that thread.
Finally, we iterate through our array of threads by calling for i in threads, and call the join method on each of these threads. This ensures that we do not proceed with the execution of our remaining code until all of our threads have finished downloading the image.
If you execute this on your machine, you should see that it almost instantaneously starts the download of the 10 different images. When the downloads finish, it again prints out that it has successfully completed, and you should see the temp folder being populated with these images.
Both the preceding scripts do exactly the same tasks using the exact same urllib.request library, but if you take a look at the total execution time, then you should see an order of magnitude improvement on the time taken for the concurrent script to fetch all 10 images.
