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Comparing performance of not nil syntax variations
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Not Nil Challenge

Swift 4.2.1 Build Status

if let _ = value or if value != nil? Comparing performance of not nil syntax variations.


Run the command below and compare the results.

$ swift test

Modify attempts property in NotNilChallengeTests class to check performance for more / fewer runs.

Test Environment

  • Device: MacBook Pro (15-inch, Mid 2015, 2.2GHz Intel Core i7, 16GB RAM)
  • OS: macOS High Sierra 10.13.3
  • Swift: 4.1.2
  • Attempts: 10,000,000

Test Results

Variant Average duration
if let _ = value 0.165 sec
if value != nil 0.184 sec


if let _ = value is about 12% faster than if value != nil.

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