String functions (join, split, format) in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to join the list of strings with a comma.

Terraform

joined_string = join(",", [1])

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

Aformat

Bsplit

Cvar.list_of_strings

Dconcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name instead of the variable holding the list.

Forgetting to provide the list argument.

The join function combines a list of strings into one string separated by the given delimiter. Here, var.list_of_strings is the list to join.

2fill in blank

medium

Complete the code to split the string into a list using a space as separator.

Terraform

split([1], var.input_string)

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

A" "

B","

C"-"

D";"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a comma or other separator instead of a space.

Not quoting the separator string.

The split function divides a string into a list using the given separator. Here, a space character " " is used to split words.

3fill in blank

hard

Fix the error in the format function to insert the variable correctly.

Terraform

formatted_string = format("Hello, %s!", [1])

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

Avar.name[0]

Bvar.name.split

Cvar.names

Dvar.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using an index or method call instead of the variable itself.

Passing a list instead of a string.

The format function replaces %s with the string variable var.name. Using var.name directly is correct.

4fill in blank

hard

Fill both blanks to join a list with a dash and then split it back into a list.

Terraform

joined = join([1], var.words)
split_list = split([2], joined)

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

A"-"

B","

D";"

Attempts:

3 left

💡 Hint

Common Mistakes

Using different separators for join and split.

Using commas or semicolons instead of dashes.

First, join the list var.words with a dash "-". Then split the joined string back by the same dash "-" to get the original list.

5fill in blank

hard

Fill all three blanks to format a string with two variables and then split the result by a space.

Terraform

formatted = format("%s %s", [1], [2])
split_result = split([3], formatted)

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

Avar.first_name

Bvar.last_name

C" "

D"-"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the order of variables.

Using wrong separator for split.

The format function inserts var.first_name and var.last_name into the string separated by a space. Then split divides the formatted string by space " " to get the list of names.

Practice

1. What does the Terraform function join(",", ["a", "b", "c"]) return?

easy

A. "a,b,c"

B. ["a", "b", "c"]

C. "a b c"

D. "abc"

Solution

1. Step 1: Understand the join function

   The join function combines list elements into a single string using the given separator.

2. Step 2: Apply join with separator ','

   Joining ["a", "b", "c"] with "," results in the string "a,b,c".

3. Final Answer:

   "a,b,c" -> Option A

4. Quick Check:

   join with comma = "a,b,c" [OK]

Hint: Join combines list items with separator into one string [OK]

Common Mistakes:

• Confusing join output with original list
• Using space instead of comma as separator
• Expecting a list instead of a string

2. Which of the following is the correct syntax to split the string "one,two,three" into a list using Terraform?

easy

A. format(",", "one,two,three")

B. split("one,two,three", ",")

C. split(",", "one,two,three")

D. join(",", "one,two,three")

Solution

1. Step 1: Recall split function syntax

   The split function takes the separator first, then the string to split.

2. Step 2: Match correct argument order

   Only split(",", "one,two,three") matches the correct syntax.

3. Final Answer:

   split(",", "one,two,three") -> Option C

4. Quick Check:

   split(separator, string) = split(",", "one,two,three") [OK]

Hint: split(separator, string) order matters in Terraform [OK]

Common Mistakes:

• Swapping arguments order in split
• Using join instead of split
• Using format instead of split

3. What is the output of this Terraform expression?

format("Hello %s, you have %d messages", "Alice", 5)

medium

A. "Hello Alice, you have 5 messages"

B. "Hello Alice, you have %d messages"

C. "Hello %s, you have %d messages"

D. "Hello %s, you have 5 messages"

Solution

1. Step 1: Understand format placeholders

   %s is replaced by string, %d by integer in order.

2. Step 2: Replace placeholders with arguments

   "Alice" replaces %s, 5 replaces %d, producing "Hello Alice, you have 5 messages".

3. Final Answer:

   "Hello Alice, you have 5 messages" -> Option A

4. Quick Check:

   format with %s and %d = formatted string [OK]

Hint: format replaces %s and %d placeholders in order [OK]

Common Mistakes:

• Not replacing placeholders
• Mixing up %s and %d types
• Expecting original string without substitution

4. Identify the error in this Terraform code snippet:

locals {
  parts = split(",", "apple,banana,orange")
  result = join(";", parts)
  message = format("Fruits: %s", result)
}

medium

A. join separator should be a list, not a string

B. split function arguments are reversed

C. format placeholder %s cannot accept a string

D. No error, code is correct

Solution

1. Step 1: Check split function usage

   split separator and string are correctly ordered.

2. Step 2: Check join and format usage

   join uses string separator ";" correctly; format uses %s for string correctly.

3. Final Answer:

   No error, code is correct -> Option D

4. Quick Check:

   split, join, format used correctly = No error, code is correct [OK]

Hint: Check argument order and placeholder types carefully [OK]

Common Mistakes:

• Swapping split arguments
• Using wrong placeholder in format
• Passing wrong types to join

5. You have a list of IP addresses: ["10.0.0.1", "10.0.0.2", "10.0.0.3"]. You want to create a single string with these IPs separated by commas, but enclosed in square brackets like this:
[10.0.0.1,10.0.0.2,10.0.0.3]
Which Terraform expression achieves this?

hard

A. join(",", format("[%s]", ["10.0.0.1", "10.0.0.2", "10.0.0.3"]))

B. format("[%s]", join(",", ["10.0.0.1", "10.0.0.2", "10.0.0.3"]))

C. split(",", format("[%s]", join(",", ["10.0.0.1", "10.0.0.2", "10.0.0.3"])))

D. format(join(",", ["10.0.0.1", "10.0.0.2", "10.0.0.3"]), "[%s]")

Solution

1. Step 1: Join IP list with commas

   Using join(",", [...]) creates "10.0.0.1,10.0.0.2,10.0.0.3".

2. Step 2: Use format to add square brackets

   Wrapping the joined string with format("[%s]", ...) adds brackets around it.

3. Final Answer:

   format("[%s]", join(",", ["10.0.0.1", "10.0.0.2", "10.0.0.3"])) -> Option B

4. Quick Check:

   join then format = format("[%s]", join(",", ["10.0.0.1", "10.0.0.2", "10.0.0.3"])) [OK]

Hint: Join first, then format to add brackets [OK]

Common Mistakes:

• Trying to format before join
• Using split instead of join
• Incorrect argument order in format