Naming rules and conventions in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a valid variable name in Python.

Python

my[1] = 10

Drag options to blanks, or click blank then click option'

A1var

B_var

C-var

Dvar!

Attempts:

3 left

💡 Hint

Common Mistakes

Starting variable names with a digit

Using special characters in variable names

Variable names can include letters, digits, and underscores but cannot start with a digit or contain special characters like '-' or '!'.

2fill in blank

medium

Complete the code to follow Python naming conventions for constants.

Python

[1] = 3.14

Drag options to blanks, or click blank then click option'

ApiValue

BPi_Value

Cpi_value

DPI_VALUE

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase letters for constants

Not using underscores to separate words

Constants in Python are usually named using all uppercase letters with underscores separating words.

3fill in blank

hard

Fix the error in the variable name to make it valid.

Python

user[1]name = 'Alice'

Drag options to blanks, or click blank then click option'

A-name

B name

C_name

D1name

Attempts:

3 left

💡 Hint

Common Mistakes

Including spaces in variable names

Starting variable names with digits

Using hyphens in variable names

Variable names cannot contain spaces or hyphens and cannot start with digits. Using an underscore is valid.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension with valid variable names and a condition.

Python

{word: len(word) for word in words if len(word) [1] [2]

Drag options to blanks, or click blank then click option'

A>

B<

C3

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid operators

Using variable names instead of numbers in conditions

The condition filters words with length greater than 3. The operator '>' and number '3' are needed.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension with uppercase keys, values, and a condition.

Python

result = [1]: [2] for word in words if len(word) [3] 4

Drag options to blanks, or click blank then click option'

Aword.upper()

Bword

C>

Dlen(word)

Attempts:

3 left

💡 Hint

Common Mistakes

Using length as key instead of uppercase word

Using wrong comparison operator

Mixing keys and values

Keys are uppercase words using word.upper(), values are the original words, and the condition filters words longer than 4 characters.

Practice

1. Which of the following is a valid variable name in Python?

easy

A. my-variable

B. 2ndVariable

C. my_variable

D. my variable

Solution

1. Step 1: Check the first character of each name

   Python variable names must start with a letter or underscore, not a number or special character.

2. Step 2: Identify invalid characters

   Names cannot contain spaces or hyphens. Only letters, digits, and underscores are allowed.

3. Final Answer:

   my_variable -> Option C

4. Quick Check:

   Valid variable name = my_variable [OK]

Hint: Variable names start with letter/underscore, no spaces or hyphens [OK]

Common Mistakes:

• Starting variable name with a number
• Using hyphens instead of underscores
• Including spaces in variable names

2. Which of these is the correct way to name a class in Python?

easy

A. MyClass

B. my_class

C. myclass

D. myClass

Solution

1. Step 1: Recall class naming convention

   Class names in Python use CapitalizedWords style (PascalCase), starting with uppercase letters.

2. Step 2: Compare options to convention

   Only 'MyClass' follows CapitalizedWords style correctly.

3. Final Answer:

   MyClass -> Option A

4. Quick Check:

   Class name style = CapitalizedWords [OK]

Hint: Class names use CapitalizedWords (PascalCase) [OK]

Common Mistakes:

• Using lowercase or underscores for class names
• Starting class names with lowercase letters
• Mixing camelCase with underscores

3. What will be the output of this code?

_count = 5
Count = 10
print(_count + Count)

medium

A. NameError

B. 15

C. SyntaxError

D. 510

Solution

1. Step 1: Understand variable names and case sensitivity

   Python variable names are case-sensitive, so '_count' and 'Count' are different variables.

2. Step 2: Calculate the sum of the two variables

   _count = 5 and Count = 10, so 5 + 10 = 15.

3. Final Answer:

   15 -> Option B

4. Quick Check:

   5 + 10 = 15 [OK]

Hint: Variable names are case-sensitive; add values accordingly [OK]

Common Mistakes:

• Ignoring case sensitivity and treating variables as same
• Expecting concatenation instead of addition
• Assuming syntax or name errors

4. Find the error in this variable name:

user-name = 'Alice'

medium

A. Variable names cannot contain hyphens

B. Variable names cannot start with a letter

C. Variable names cannot contain underscores

D. Variable names cannot be lowercase

Solution

1. Step 1: Identify invalid characters in variable names

   Hyphens are not allowed in Python variable names because they are interpreted as minus signs.

2. Step 2: Confirm other options are incorrect

   Variable names can start with letters, contain underscores, and be lowercase.

3. Final Answer:

   Variable names cannot contain hyphens -> Option A

4. Quick Check:

   Hyphens not allowed in names [OK]

Hint: No hyphens in variable names; use underscores instead [OK]

Common Mistakes:

• Using hyphens instead of underscores
• Thinking variable names can't start with letters
• Confusing underscores with invalid characters

5. You want to create a dictionary where keys are variable names and values are their types. Which naming style is best for the keys?

variables = { 'UserName': str, 'user_age': int, '2ndUser': str }

Which keys follow Python naming rules and conventions?

hard

A. 'user_age' only

B. All keys are valid

C. 'UserName' only

D. 'UserName' and 'user_age' only

Solution

1. Step 1: Check each key for naming rules

   'UserName' starts with a letter and uses CapitalizedWords (good for class names). 'user_age' uses lowercase with underscore (good for variables). '2ndUser' starts with a number, which is invalid.

2. Step 2: Identify keys following naming conventions

   'UserName' and 'user_age' follow naming rules; '2ndUser' does not.

3. Final Answer:

   'UserName' and 'user_age' only -> Option D

4. Quick Check:

   Keys must start with letter; numbers not allowed [OK]

Hint: Keys must start with letter; numbers not allowed [OK]

Common Mistakes:

• Allowing keys starting with numbers
• Ignoring naming conventions for readability
• Assuming all strings are valid variable names