Supervised learning: Supervised learning is the learning of the model where with input variable ( say, x) and an output variable (say, Y) and an algorithm to map the input to the output.

That is, Y = f(X)

Unsupervised Learning: Unsupervised learning is where only the input data (say, X) is present and no corresponding output variable is there.

Here are the differences:

Data Science is a blend of various tools, algorithms, and machine learning principles with the goal to discover hidden patterns from the raw data.

Data science is a multi-disciplinary field that uses scientific methods, processes, algorithms and systems to extract knowledge and insights from structured and unstructured data. 

Here are the difference between Data Science, Machine Learning and AI.

Python files are compiled to bytecode, which is then executed by the host. Python automatically compiles your script to compiled code, so called byte code, before running it.

When a module is imported for the first time, or when the source is more recent than the current compiled file, a .pyc file containing the compiled code will usually be created in the same directory as the .py file. When you run the program next time, Python uses this file to skip the compilation step.
 

Use below code to get the home directory:

import os

print (os.path.expanduser('~'))

Suppose file contain text "Hello Capital World!" 

with open('/mypath/mycapitalfile.txt') as countletter:
    count = 0
    file_text = countletter.read()
    
    for character in file_text:
        if character.isupper():
            count += 1

print("Total Capital Letters in file:", count)  

This will print, Total Capital Letters in file: 3

Another efficient way of doing this:

str = 'Hello World!'
print(str)

This will print Hello World!

Global Variables: Variables declared outside a function or in global space are called global variables. These variables can be accessed by any function in the program.

Local Variables: Any variable declared inside a function is known as a local variable. This variable is present in the local space and not in the global space.

Example:

Pass means, no-operation Python statement, or in other words it is a place holder in compound statement, where there should be a blank left and nothing has to be written there.

Yes! Python is a case sensitive programming language.