Given val data: List?, which Kotlin expression safely returns the length of the first string or null if data or the first element is null?

hard📝 Application Q8 of 15

Kotlin - Null Safety

Given val data: List?, which Kotlin expression safely returns the length of the first string or null if data or the first element is null?

Adata.get(0)?.length

Bdata?.get(0)?.length

Cdata?.get(0).length

Ddata.get(0).length

Step-by-Step Solution

Solution:

Step 1: Understand variable types
data is nullable list of nullable strings.
Step 2: Access first element safely
Use data?.get(0) to safely get first element or null if list is null.
Step 3: Access length safely
Use ?.length to safely get length if first element is not null.
Final Answer:
data?.get(0)?.length -> Option B
Quick Check:
Safe call needed on both list and element [OK]

Quick Trick: Use ?. twice to safely access nested nullable elements [OK]

Common Mistakes:

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