Built-in string functions in SASS

Introduction

Built-in string functions help you change and check text in your styles easily. They save time and make your code cleaner.

When you want to join two words or parts of text together.

When you need to check if a word or letter is inside a text.

When you want to locate the position of a substring in a string.

When you want to get a part of a text, like the first few letters.

When you want to find where a word or letter appears in text.

Syntax

SASS

function-name(string, [optional-arguments])

Most string functions take a string as the first input.

Some functions need extra information like the part of the string to get.

Examples

Returns the number of characters in the string "Hello".

SASS

string.length("Hello")

Returns the position where "Sass" first appears: 7 (positions start at 1).

SASS

string.index("Hello Sass", "Sass")

Inserts "hello " at position 1 in "world", resulting in "hello world".

SASS

string.insert("hello ", "world", 1)

Gets characters from position 2 to 4: "bcd".

SASS

string.slice("abcdef", 2, 4)

Sample Program

This Sass code uses built-in string functions to create a greeting by inserting "Hello " before "Sass". It then finds the length of the greeting and the position of "Sass" in it. The results show on the webpage with clear labels.

SASS

@use "sass:string";

$word: "Sass";
$greeting: string.insert("Hello ", $word, 7);
$length: string.length($greeting);
$position: string.index($greeting, $word);

body {
  font-family: Arial, sans-serif;
  padding: 1rem;
}

.result::before {
  content: "#{$greeting}";
  display: block;
  margin-bottom: 1rem;
}

.result {
  margin-bottom: 1rem;
  font-weight: bold;
}

.output-length::after {
  content: "Length: #{$length}";
  display: block;
  margin-top: 0.25rem;
  color: #555;
}

.output-position::after {
  content: "Position of \"Sass\": #{$position}";
  display: block;
  margin-top: 0.25rem;
  color: #555;
}

Important Notes

Remember to import the string module in Sass to use these functions.

Positions in strings start at 1, not 0.

String functions help keep your styles dynamic and easy to update.

Summary

Built-in string functions let you work with text inside your Sass code.

You can measure length, locate substrings, insert, and slice strings easily.

Using these functions makes your styles more flexible and powerful.

Practice

1. Which Sass built-in string function returns the length of a string?
length("hello")

easy

A. Returns the string in uppercase

B. Returns the number of characters in the string

C. Returns the string reversed

D. Returns the first character of the string

Solution

1. Step 1: Understand the length() function

   The length() function in Sass returns how many characters are in a string.

2. Step 2: Apply to the example string

   For the string "hello", the length is 5 characters.

3. Final Answer:

   Returns the number of characters in the string -> Option B

4. Quick Check:

   length("hello") = 5 [OK]

Hint: Remember length() counts characters in a string [OK]

Common Mistakes:

• Confusing length() with uppercase conversion
• Thinking length() returns the first character
• Mixing length() with reverse functions

2. Which of the following is the correct syntax to convert a string to uppercase in Sass?

easy

A. uppercase("text")

B. to-upper-case("text")

C. toUpperCase("text")

D. to-upper("text")

Solution

1. Step 1: Recall Sass string uppercase function

   The correct Sass function to convert a string to uppercase is uppercase().

2. Step 2: Check syntax correctness

   The function is called as uppercase("text"), which matches uppercase("text").

3. Final Answer:

   uppercase("text") -> Option A

4. Quick Check:

   uppercase("text") converts to "TEXT" [OK]

Hint: Use uppercase() exactly as shown for capital letters [OK]

Common Mistakes:

• Using camelCase like toUpperCase() which is not Sass syntax
• Adding dashes incorrectly in function names
• Confusing with CSS text-transform property

3. What is the output of this Sass code?

$str: "Sass";
$result: str-insert($str, "3", 3);

What is the value of $result?

medium

A. "Sass3"

B. "Sas3s"

C. "S3ass"

D. "Sa3ss"

Solution

1. Step 1: Understand str-insert() function

   This function inserts a string into another string at a given index (1-based).

2. Step 2: Apply insertion at position 3

   Original string is "Sass". Insert "3" at position 3 means after the second character: "Sa" + "3" + "ss" = "Sa3ss".

3. Final Answer:

   "Sa3ss" -> Option D

4. Quick Check:

   str-insert("Sass", "3", 3) = "Sa3ss" [OK]

Hint: Remember str-insert uses 1-based index for insertion [OK]

Common Mistakes:

• Using 0-based index instead of 1-based
• Inserting at wrong position
• Confusing str-insert with str-slice

4. Identify the error in this Sass code:

$text: "Hello";
$new-text: str-slice($text, 2, 1);

medium

A. Start index is greater than end index, causing empty string

B. str-slice requires three arguments, missing one

C. Variable names must start with uppercase letters

D. Strings cannot be sliced in Sass

Solution

1. Step 1: Check str-slice() parameters

   The function takes a string, a start index, and an optional end index. Here start=2, end=1.

2. Step 2: Analyze index order

   Since start index (2) is greater than end index (1), the slice returns an empty string, which is likely unintended.

3. Final Answer:

   Start index is greater than end index, causing empty string -> Option A

4. Quick Check:

   str-slice("Hello", 2, 1) = "" (empty) [OK]

Hint: Ensure start index ≤ end index in str-slice() [OK]

Common Mistakes:

• Assuming str-slice needs three arguments always
• Thinking variable names must be uppercase
• Believing strings can't be sliced in Sass

5. You want to create a Sass function that returns the first three characters of a string in uppercase. Which code correctly achieves this?

hard

A. @function first-three-uppercase($str) { @return str-insert(uppercase($str), 3, 1); }

B. @function first-three-uppercase($str) { @return uppercase(str-slice($str, 1)); }

C. @function first-three-uppercase($str) { @return str-slice(uppercase($str), 1, 3); }

D. @function first-three-uppercase($str) { @return uppercase(str-insert($str, 3, 1)); }

Solution

1. Step 1: Understand the goal

   We want the first three characters of the string in uppercase: uppercase first, then slice precisely.

2. Step 2: Analyze each option

   @function first-three-uppercase($str) { @return str-slice(uppercase($str), 1, 3); } uppercases whole string, then slices first 3 characters -- correct.
   @function first-three-uppercase($str) { @return uppercase(str-slice($str, 1)); } str-slice from 1 to end (no end index), uppercases entire string -- incorrect, too many chars.
   @function first-three-uppercase($str) { @return str-insert(uppercase($str), 3, 1); } uses str-insert incorrectly and passes number 3 as insert string -- error.
   @function first-three-uppercase($str) { @return uppercase(str-insert($str, 3, 1)); } similar str-insert misuse -- incorrect.

3. Final Answer:

   @function first-three-uppercase($str) { @return str-slice(uppercase($str), 1, 3); } -> Option C

4. Quick Check:

   str-slice(uppercase($str), 1, 3) returns first 3 uppercase chars [OK]

Hint: Uppercase full string first, then slice first 3 chars [OK]

Common Mistakes:

• Forgetting end index in str-slice causing full string slice
• Using str-insert instead of str-slice
• Passing numbers as insert strings causing type error