Ruby - Blocks, Procs, and Lambdas
You want to create an array of lambdas where each lambda returns the square of its index (0 to 4). Which code correctly achieves this using closures?
You want to create an array of lambdas where each lambda returns the square of its index (0 to 4). Which code correctly achieves this using closures?
hard📝 Application Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Understand variable capture in closures
Using block variable i directly in lambda captures the variable, which may change.Step 2: Use a local variable to capture current value
Assign i to val inside the block, then use val in lambda to capture the value at each iteration.Final Answer:
arr = [] 5.times do |i| val = i arr << lambda { val * val } end -> Option BQuick Check:
Use local variable to fix closure capture [OK]
Quick Trick: Assign block variable to local var before lambda to capture value [OK]
Common Mistakes:
- Using block variable directly causing all lambdas to return last value
- Confusing * and ** operators
- Ignoring variable binding inside closures
Master "Blocks, Procs, and Lambdas" in Ruby
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