String Concatenation and Formatting
By the end of this lesson, you'll be able to:
- Build a message by concatenating strings and variables
- Use String.format() to build a message more readably
- Explain when formatting is preferable to plain concatenation
Prerequisites: "Type Conversion vs Casting"
Concatenation, revisited
String name = 'Thabo';
Integer orderNumber = 4821;
String message = 'Hi ' + name + ', your order #' + orderNumber + ' is confirmed.';This works, but gets harder to read as more variables join in — every + is a small interruption to the sentence you're building.
String.format() as an alternative
String message = String.format(
'Hi {0}, your order #{1} is confirmed.',
new List<String>{ name, String.valueOf(orderNumber) }
);{0} and {1} are placeholders, filled in order from the list that follows. Note that String.format() expects String values in that list — non-string values (like our Integer) need converting first, using exactly the String.valueOf() you met last lesson.
A real business example: Retail
An order-confirmation message with several dynamic parts — customer name, order number, delivery date — is a natural fit for String.format(): the sentence structure stays visible and readable, instead of getting broken up by + operators every few words.
Trade-offs and when NOT to use this
For a simple, one- or two-variable message, plain + concatenation is often just as readable and involves less ceremony (no building a List). String.format() earns its keep once you have three or more variables, or when the same message template gets reused in multiple places.
Exercise
Using String.format(), build a message: 'Case #{caseNumber} was closed after {days} days.' — with caseNumber '00012345' and days 3.
Show hint
Remember: String.format() needs a List<String>, and days needs converting first with String.valueOf().
String Concatenation and Formatting Quiz
My Notes
Log in to keep private notes on this lesson.
Questions about this lesson
No questions yet — be the first to ask.
Log in to ask a question about this lesson.
Summary
Beyond the + operator from Module 3, Apex offers String.format() for building messages with placeholders — often more readable than a long chain of + operators, especially once several variables are involved.