Kotlin - Collections Fundamentals
You have a list of user names and want to print how many users are online only if the list is not empty. Which Kotlin code snippet correctly does this?
You have a list of user names and want to print how many users are online only if the list is not empty. Which Kotlin code snippet correctly does this?
hard📝 Application Q15 of 15
Step-by-Step Solution
Solution:
Step 1: Check condition for non-empty list
Usingusers.size > 0correctly checks if the list has one or more elements.Step 2: Verify printing statement
The print statement uses string interpolation to show the number of users online.Step 3: Analyze incorrect options
isEmpty()checks for empty, so if (users.isEmpty()) println("Online users: ${users.size}") prints when empty, which is wrong.countis a function, socount == 0is invalid.isNotEmptywithout parentheses is incorrect syntax.Final Answer:
if (users.size > 0) println("Online users: ${users.size}") -> Option BQuick Check:
Check size > 0 for non-empty list [OK]
Quick Trick: Use size > 0 or isNotEmpty() with parentheses [OK]
Common Mistakes:
MISTAKES- Using isEmpty() to check for non-empty
- Calling count without parentheses
- Omitting parentheses on isNotEmpty()
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