Beginner 15 min read

Text: String

By the end of this lesson, you'll be able to:

Create and assign String variables
Join strings together using concatenation
Use at least two built-in String methods

Prerequisites: "Numbers"

Creating and joining strings

String firstName = 'Amara';
String lastName = 'Okafor';
String fullName = firstName + ' ' + lastName;
System.debug(fullName); // Amara Okafor

String firstName = 'Amara'; — declares a String (text) variable. Apex strings use single quotes.
String lastName = 'Okafor'; — same pattern, for the surname.
String fullName = firstName + ' ' + lastName; — the + operator concatenates (joins) firstName, a literal space, and lastName into one new string.
System.debug(fullName); — logs fullName, printing Amara Okafor.

Useful built-in methods

A String variable comes with methods you call using dot notation:

String raw = '  Retail Customer  ';
System.debug(raw.trim());        // 'Retail Customer' — whitespace removed
System.debug(raw.toUpperCase()); // '  RETAIL CUSTOMER  '
System.debug(raw.contains('Customer')); // true

String raw = ' Retail Customer '; — declares raw with extra spaces on either side, deliberately, to show what the methods below actually do.
System.debug(raw.trim()); — calls .trim(), which returns a new string with leading/trailing whitespace removed, then logs it.
System.debug(raw.toUpperCase()); — calls .toUpperCase(), returning raw with every letter capitalized. raw itself never changes — each method call returns a brand-new string.
System.debug(raw.contains('Customer')); — calls .contains('Customer'), which returns a Boolean — true, since 'Customer' does appear inside raw.

A real business example: Retail

A retail order confirmation might build a message like:

String customerName = 'Priya Sharma';
String orderNumber = '48213';
String message = 'Hi ' + customerName + ', your order #' + orderNumber + ' has shipped!';

String customerName = 'Priya Sharma'; — the customer's name, as text.
String orderNumber = '48213'; — the order number, stored as a String here (not a number) because it's only ever used as display text, never in arithmetic.
String message = ... — builds one final message by concatenating five pieces together with +: a greeting, the name, more text, the order number, and a closing phrase.

This exact pattern — concatenating variables into a human-readable message — shows up constantly in real Apex code, from email bodies to debug logs to error messages.

Common mistakes

Forgetting spaces when concatenating. firstName + lastName gives AmaraOkafor, not Amara Okafor — the space needs to be added explicitly.
Comparing strings with == when case might differ. 'Apex' == 'apex' is false — use .equalsIgnoreCase() when case shouldn't matter.

String methods in practice

String email = 'Jane.Doe@Example.com';
String normalized = email.toLowerCase().trim();
System.debug(normalized); // jane.doe@example.com

String email = 'Jane.Doe@Example.com'; — the raw input, with mixed case.
String normalized = email.toLowerCase().trim(); — chains two methods: .toLowerCase() runs first and returns a lowercase copy, then .trim() runs on that result, removing any surrounding whitespace.
System.debug(normalized); — logs the cleaned-up result: jane.doe@example.com.

Exercise

Declare a String greeting with extra spaces around it, like ' hello '. Debug its trimmed, uppercase version in one chained expression.

Show hint

You can chain .trim().toUpperCase() directly onto the variable.

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APEX

Execution Results

Run your code to see the result.

Text: String Quiz

1. What does the + operator do when used between two String values?

Joins (concatenates) them into one String Adds their character counts Compares them for equality It causes a compile error

2. 'Apex' == 'apex' evaluates to true in Apex.

True False — string comparison with == is case-sensitive

Leaderboard

1. Monde Masiza 2/2

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Summary

String is Apex's text type — anything in quotes. Strings come with a rich set of built-in methods for common tasks like changing case, trimming whitespace, and checking contents, which you'll reach for constantly.

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