How do you instantiate an object from a class in Python?
- create Object from Class;
- new Object(Class);
- obj = Class()
- object = new Class()
To instantiate an object from a class in Python, you use the syntax object_name = Class_name(). The other options are not valid syntax for object instantiation in Python.
How can you pass dynamic data from a Python back-end to a JavaScript variable in the front-end?
- Include Python variables directly in JavaScript code.
- Use AJAX requests to fetch data from the Python back-end.
- Use HTTP cookies to store Python data for JavaScript to access.
- Use WebSockets to establish a real-time connection.
To pass dynamic data from a Python back-end to a JavaScript variable, you typically use AJAX (Asynchronous JavaScript and XML) requests. This allows you to make asynchronous requests to the back-end, retrieve data, and update JavaScript variables without refreshing the entire page.
How can you perform element-wise multiplication of two NumPy arrays?
- array1 * array2
- array1.multiply(array2)
- np.multiply(array1, array2)
- np.multiply_elements(array1, array2)
To perform element-wise multiplication of two NumPy arrays, you can simply use the * operator between the two arrays. NumPy overloads arithmetic operations to work element-wise.
How can you optimize the performance of static files (CSS, JS, Images) in a web application developed using Python frameworks?
- Compress and minify static files
- Optimize database queries
- Use serverless functions
- Utilize a Content Delivery Network (CDN)
Utilizing a Content Delivery Network (CDN) is a highly effective way to optimize the performance of static files. CDNs distribute your files across multiple geographically distributed servers, reducing latency and improving load times.
How can you optimize the recursive Fibonacci function with dynamic programming?
- Convert it to an iterative function
- Implement a tail-recursive version
- Increase the base case value
- Use memoization to store intermediate results
Dynamic programming can optimize the recursive Fibonacci function by using memoization to store previously calculated Fibonacci numbers, reducing redundant calculations. The other options don't directly optimize the recursive approach.
How would you run a Python script from the command line and pass arguments to it?
- python execute script.py with-args arg1 arg2
- python -r script.py arg1 arg2
- python run script.py --args arg1 arg2
- python script.py arg1 arg2
To run a Python script from the command line and pass arguments, you use the python command followed by the script name and the arguments separated by spaces, like python script.py arg1 arg2. This allows you to pass arguments to your script for processing.
How would you set a breakpoint in a Python script to start debugging?
- breakpoint()
- debug()
- pause()
- stop()
In Python 3.7 and later, you can set a breakpoint by using the breakpoint() function. It pauses the script's execution and enters the interactive debugger at that point, allowing you to examine variables and step through code.
How would you set up a custom command in Django that can be run using the manage.py file?
- a. Create a Python script with your command logic, save it in the Django project directory, and add an entry in the commands list in the project's __init__.py.
- b. Create a Python script with your command logic and place it in the management/commands directory of your Django app.
- c. Modify the Django source code to add your custom command.
- d. Use a third-party package for custom commands.
To set up a custom management command in Django, you should create a Python script in the management/commands directory of your app. Django will automatically discover and make it available through manage.py. Options a, c, and d are not standard practices.
How would you split a dataset into training and testing sets using Scikit-learn?
- dataset_split(data, 0.2)
- split_data(data, train=0.8, test=0.2)
- train_and_test(data, test_ratio=0.2)
- train_test_split(data, test_size=0.2)
You would use the train_test_split function from Scikit-learn to split a dataset into training and testing sets. It's a common practice in machine learning to use an 80-20 or 70-30 train-test split to evaluate model performance. The other options are not valid functions in Scikit-learn.
How would you test a function that does not return a value, but prints something out, using unittest?
- Manually check the printed output during testing.
- Redirect the printed output to a file and compare the file contents in the test case.
- This cannot be tested with unittest as it's impossible to capture printed output.
- Use the unittest.mock library to capture the printed output and compare it to the expected output.
To test a function that prints something without returning a value, you can use the unittest.mock library to capture the printed output and then compare it to the expected output in your test case. This allows you to assert that the function is producing the expected output.