Heredoc syntax for multiline strings in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a multiline string using heredoc syntax.

Ruby

text = <<[1]
This is a multiline string.
It spans multiple lines.
[1]

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

A'END'

B"END"

CEND

Dend

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around the delimiter which changes the string behavior.

Mismatching the starting and ending delimiters.

The heredoc delimiter should be an unquoted identifier like END to start and end the multiline string.

2fill in blank

medium

Complete the code to create a heredoc string that preserves indentation.

Ruby

text = <<~[1]
  Line one
  Line two
[1]

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

AHEREDOC

BEND

CDOC

DTEXT

Attempts:

3 left

💡 Hint

Common Mistakes

Using different delimiter names at start and end.

Not using the tilde (~) to enable indentation stripping.

The <<~END syntax allows indentation to be stripped from the heredoc content.

3fill in blank

hard

Fix the error in the heredoc syntax to correctly assign a multiline string.

Ruby

message = <<[1]
Hello,
This is a test.
[1]

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

AMSG

B'MSG'

C"MSG"

Dmsg

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around the delimiter.

Using lowercase delimiter which is uncommon and may cause confusion.

The delimiter must be an unquoted identifier and match exactly at start and end.

4fill in blank

hard

Fill both blanks to create a heredoc string with interpolation enabled.

Ruby

name = "Alice"
text = <<[1]
Hello, #{name}!
[2]

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

AEND

B"END"

C'END'

Dend

Attempts:

3 left

💡 Hint

Common Mistakes

Quoting the delimiter which disables interpolation.

Mismatching the delimiters.

Using an unquoted delimiter like END enables string interpolation inside the heredoc.

5fill in blank

hard

Fill all three blanks to create a heredoc string that disables interpolation and preserves indentation.

Ruby

name = "Bob"
text = <<~[1][2]
Hello, #{name}!
  Indented line.
[3]

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

A~

B'

CEND

D"

Attempts:

3 left

💡 Hint

Common Mistakes

Using double quotes which enable interpolation.

Omitting the tilde which keeps indentation.

Using <<~'END' disables interpolation (due to single quotes) and strips indentation (due to ~).

Practice

1. What is the main purpose of using heredoc syntax in Ruby?

easy

A. To declare variables with fixed values

B. To create single-line comments

C. To write multiline strings easily without using escape characters

D. To define methods with multiple parameters

Solution

1. Step 1: Understand what heredoc does

   Heredoc syntax allows writing strings that span multiple lines without needing escape characters like \n.

2. Step 2: Compare options

   Declaring variables with fixed values, creating single-line comments, and defining methods with multiple parameters describe unrelated Ruby features. Only writing multiline strings easily without using escape characters correctly describes heredoc's purpose.

3. Final Answer:

   To write multiline strings easily without using escape characters -> Option C

4. Quick Check:

   Heredoc = multiline strings [OK]

Hint: Heredoc is for easy multiline text, not comments or methods [OK]

Common Mistakes:

• Confusing heredoc with comments
• Thinking heredoc defines methods
• Assuming heredoc is for variables only

2. Which of the following is the correct syntax to start a heredoc string named TEXT in Ruby?

easy

A. << TEXT

B. <TEXT

C.

D. TEXT<<

Solution

1. Step 1: Recall heredoc start syntax

   Heredoc starts with << followed immediately by an identifier, e.g., <

2. Step 2: Check each option

   <<TEXT matches the correct syntax. << TEXT with space is invalid. Arrangements like

3. Final Answer:

   <<TEXT -> Option B

4. Quick Check:

   Start heredoc with <<IDENTIFIER [OK]

Hint: Heredoc starts with << followed by the identifier [OK]

Common Mistakes:

• Putting identifier before <<
• Using incorrect symbols like < or - wrongly
• Confusing heredoc start with end

3. What will be the output of this Ruby code?

text = <<~GREETING
  Hello,
    Welcome to Ruby!
GREETING
puts text

medium

A. Hello,
Welcome to Ruby!

B. Hello,
Welcome to Ruby!

C. Hello,
Welcome to Ruby!

D. !ybuR ot emocleW
,olleH

Solution

1. Step 1: Understand <<~ operator

   The <<~ syntax removes leading spaces common to all lines, aligning text left.

2. Step 2: Analyze the given text

   Original lines have 2 spaces before 'Hello,' and 4 before 'Welcome'. The common indent is 2 spaces, so those are removed.

3. Step 3: Resulting output

   After removing 2 spaces, 'Hello,' starts at column 0, 'Welcome...' starts with 2 spaces.

4. Final Answer:

   Hello, Welcome to Ruby! -> Option A

5. Quick Check:

   <<~ removes common indent [OK]

Hint: <<~ removes common leading spaces from all lines [OK]

Common Mistakes:

• Ignoring <<~ and expecting original indentation
• Confusing \n with actual new lines
• Assuming all spaces are removed

4. Identify the error in this Ruby heredoc code:

message = <

medium

A. The string must be enclosed in quotes

B. The starting identifier should be lowercase

C. The heredoc must use <<~ instead of <<

D. The ending identifier must match exactly and be alone on its line

Solution

1. Step 1: Check heredoc start and end identifiers

   Heredoc must end with the same identifier used to start it, alone on a line with no spaces.

2. Step 2: Analyze given code

   Start identifier is GREETING but end identifier is END, which is incorrect.

3. Final Answer:

   The ending identifier must match exactly and be alone on its line -> Option D

4. Quick Check:

   Start and end identifiers must match [OK]

Hint: End heredoc with the exact same word alone on a line [OK]

Common Mistakes:

• Mismatching start and end identifiers
• Adding spaces after end identifier
• Using lowercase instead of uppercase identifiers

5. You want to create a multiline string with indentation preserved but also want to remove leading spaces common to all lines for neat code. Which heredoc syntax should you use in Ruby?

hard

A. <<~TEXT

B. <<-TEXT

C. <TEXT

D. <<=TEXT

Solution

1. Step 1: Understand heredoc variants

   <<TEXT preserves all spaces; <<-TEXT allows indenting the end marker; <<~TEXT removes common leading spaces from all lines.

2. Step 2: Match requirement

   To keep indentation inside the string but remove common leading spaces for clean code, <<~TEXT is the correct choice.

3. Final Answer:

   <<~TEXT -> Option A

4. Quick Check:

   <<~ trims common indent [OK]

Hint: <<~ removes common indent, use it for clean multiline strings [OK]

Common Mistakes:

• Using <<- which only affects end marker indentation
• Using << which keeps all spaces
• Assuming <<= is valid syntax