Beginning Swift Programming by Wei-Meng Lee

Author:Wei-Meng Lee [Lee, Wei-Meng]
Language: eng
Format: azw3, pdf
ISBN: 9781119009320
Publisher: Wiley
Published: 2014-12-03T16:00:00+00:00

Where Clause

You can use the Switch statement together with a where clause to check for additional conditions. For example, if you wanted to check if the scores for both subjects are greater than 80, you could write the following case:

//---(math, science)--- var scores = (90,90) switch scores { case (0,0): println("This is not good!") case (100,100): println("Perfect score!") case let (math, science) where math > 80 && science > 80: println("Well done!") case (50...100, let science): println("Math pass!") if science<50 { println("But Science fail!") } else { println("And Science also pass!") } case (let math, 50...100): println("Science pass!") if math<50 { println("But Math fail!") } else { println("And Math also pass!") } case let (math, science): println("Math is \(math) and Science is \(science)") }

In the preceding code snippet, the third case assigns the scores of the math and science subjects to the temporary variables math and science, respectively, and uses the where clause to specify the condition that the scores for both math and science must be greater than 80. The preceding example will output the following statement:

Well done!

If you want to match the case where the math score is greater than the science score, you can specify the following where clause:

case let (math, science) where math > science: println("You have done well for Math!")

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