How text is stored (ASCII, Unicode) in Intro to Computing - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert the character 'A' to its ASCII number.

Intro to Computing

ascii_value = ord([1])

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

A"A"

BA

C'A'

D'a'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the character without quotes causes an error.

Using double quotes is also correct but only one option is correct here.

The ord() function takes a single character as a string and returns its ASCII (or Unicode) number. The character must be in quotes.

2fill in blank

medium

Complete the code to convert the ASCII number 66 back to its character.

Intro to Computing

char = chr([1])

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

A66

B"66"

C'66'

Dchr

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string like '66' causes a TypeError.

Passing the function name instead of a number causes an error.

The chr() function takes an integer ASCII (or Unicode) code and returns the corresponding character. The input must be an integer, not a string.

3fill in blank

hard

Fix the error in the code that tries to get the ASCII code of the string 'Hello'.

Intro to Computing

code = ord([1])

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

A'Hello'

B"Hello"

CHello

D'H'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the whole string causes a TypeError.

Not using quotes around the character causes an error.

The ord() function only works with a single character. To get the ASCII code of the first letter in 'Hello', pass just 'H' in quotes.

4fill in blank

hard

Fill both blanks to create a dictionary mapping each character in 'abc' to its ASCII code.

Intro to Computing

ascii_map = { [1] for [2] in 'abc' }

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

A{char: ord(char)}

Bchar

Cc

Dx

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names in the loop.

Missing the colon between key and value in the dictionary.

This dictionary comprehension loops over each character in the string 'abc' and maps it to its ASCII code using ord().

5fill in blank

hard

Fill all three blanks to create a dictionary of characters and their Unicode codes for 'ñöç'.

Intro to Computing

unicode_map = { [1]: [2] for [3] in 'ñöç' }

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

Ach

Bord(ch)

Dchar

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Not calling ord() correctly.

This dictionary comprehension uses the variable ch to loop over each character in the string 'ñöç' and maps each character to its Unicode code using ord().

Practice

1. What is the main purpose of ASCII in text storage?

easy

A. To compress text files

B. To store images and videos

C. To represent English letters and symbols as numbers

D. To encrypt text data

Solution

1. Step 1: Understand ASCII's role

   ASCII is a code that assigns numbers to English letters and symbols so computers can store and process them.

2. Step 2: Compare with other options

   Options A, B, and D describe unrelated functions like storing images, compressing, or encrypting, which ASCII does not do.

3. Final Answer:

   To represent English letters and symbols as numbers -> Option C

4. Quick Check:

   ASCII = English letters as numbers [OK]

Hint: ASCII is for English letters and symbols only [OK]

Common Mistakes:

• Thinking ASCII stores images or videos
• Confusing ASCII with encryption
• Assuming ASCII compresses text

2. Which of the following is a correct ASCII code for the uppercase letter 'A'?

easy

A. 97

B. 65

C. 128

D. 256

Solution

1. Step 1: Recall ASCII codes for letters

   In ASCII, uppercase 'A' is represented by the number 65.

2. Step 2: Check other options

   97 is lowercase 'a', 128 and 256 are outside standard ASCII range.

3. Final Answer:

   65 -> Option B

4. Quick Check:

   ASCII 'A' = 65 [OK]

Hint: Uppercase 'A' in ASCII is 65 [OK]

Common Mistakes:

• Mixing uppercase and lowercase ASCII codes
• Choosing numbers outside ASCII range
• Confusing ASCII with Unicode codes

3. Given the Unicode code point U+1F600, what character does it represent?

medium

A. Smiling face emoji 😀

B. Latin capital letter A

C. Greek letter alpha

D. Digit zero '0'

Solution

1. Step 1: Identify Unicode code point

   U+1F600 is a Unicode code point in the emoji range.

2. Step 2: Match code point to character

   U+1F600 corresponds to the smiling face emoji 😀, not letters or digits.

3. Final Answer:

   Smiling face emoji 😀 -> Option A

4. Quick Check:

   Unicode U+1F600 = 😀 emoji [OK]

Hint: Unicode U+1F600 is a common emoji code [OK]

Common Mistakes:

• Assuming all Unicode codes are letters
• Confusing emoji codes with ASCII
• Picking digits or Greek letters incorrectly

4. A program tries to store the character 'ñ' using ASCII encoding. What is the likely problem?

medium

A. The character 'ñ' is not in ASCII, causing incorrect storage

B. 'ñ' is stored correctly because ASCII supports all characters

C. The program will convert 'ñ' to uppercase automatically

D. ASCII will store 'ñ' as the number 10

Solution

1. Step 1: Check ASCII character range

   ASCII supports only basic English letters and symbols, not special characters like 'ñ'.

2. Step 2: Understand encoding limitations

   Trying to store 'ñ' in ASCII will cause incorrect storage or errors because it is outside ASCII's range.

3. Final Answer:

   The character 'ñ' is not in ASCII, causing incorrect storage -> Option A

4. Quick Check:

   ASCII lacks 'ñ' character [OK]

Hint: ASCII covers only basic English letters [OK]

Common Mistakes:

• Assuming ASCII supports all characters
• Thinking ASCII converts characters automatically
• Believing ASCII stores 'ñ' as number 10

5. You want to store text containing English letters, Chinese characters, and emojis. Which encoding should you use?

hard

A. ASCII only

B. Morse code

C. Binary code for numbers only

D. Unicode (like UTF-8)

Solution

1. Step 1: Identify text types

   The text includes English letters, Chinese characters, and emojis, which require a wide range of characters.

2. Step 2: Choose suitable encoding

   ASCII supports only English letters; binary code and Morse code are not text encodings. Unicode (like UTF-8) supports all these characters.

3. Final Answer:

   Unicode (like UTF-8) -> Option D

4. Quick Check:

   Unicode supports all languages and emojis [OK]

Hint: Use Unicode for all languages and emojis [OK]

Common Mistakes:

• Choosing ASCII for non-English text
• Confusing binary code with text encoding
• Selecting Morse code for digital text storage