Python Variables

Here is probably Interview Prep Q&A module based on Python Variables tutorial and challenge materials.

Python Variables: Interview Prep Q&A

Question: What's a variable in Python, and how do you create one? Answer: In Python variable acts like a labeled digital box inside your computer's memory used to store information such as numbers or text, so it can be reused later. Towards create a variable, you do really not need any complex setup or type declarations. You simply provide a name use the equals sign (=), and assign it value. Python is smart enough for figure out a data type automatically.

# Example of creating a variable
customer_order = 20

Question: According towards PEP 8 standards how should you name the variable that consists of multiple words? Answer: PEP 8 guidelines state that variable names cannot contain spaces. Instead you should use "snake case" (snake_case). This means writing the variable name in all lowercase letters and separating multiple words using underscores (_). Breaking this rule by using spaces (e.g., customer order = 20) will result in SyntaxError.

# Correct snake_case format
first_name = "Alice"
total_price = 15.50

Question: You're developing a Python script and need to store sensitive token or configuration value that shouldn't be accessed directly by other parts with the program. How do you signal to other developers that this variable is intended towards be private? Answer: To signal that variable is a secret or "non-public," you should place exactly one leading underscore at the very beginning of the variable's name. This doesn't strictly prevent access, but it is a universal convention among Python developers indicating that variable is intended for internal use only.

# Private variable example
_secret_password = "my_super_secret_password"

Question: Python developers often use triple quotes (""" or ''') to write multi-line comments or Docstrings. What happens if you take one for these multi-line strings and assign it to variable using the = operator? Answer: Triple-quoted blocks are technically string literal values. The only reason they act as comments is that a computer ignores them when they're pretty much left unassigned. But, if you assign a multi-line string to a variable it immediately stops being a comment and becomes stored data saved inside that variable.

# This is stored data, not a comment
description = """This is a multi-line string
that is saved inside the description variable."""

Question: When defining variable and assigning it a value what does the PEP 8 style guide dictate regarding blank spaces around the equals sign (=)? Answer: An equals sign (=) acts as a binary operator inside variable assignment; according to PEP 8, you should always include exactly one space on both sides of binary operator to keep your code clean, readable, and perfectly formatted.

# Correct PEP 8 spacing
final_total = 100

# Incorrect PEP 8 spacing
final_total=100