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Clarify the type of for comprehension. #1657

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Clarify the type of for comprehension. #1657

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2 changes: 1 addition & 1 deletion _tour/for-comprehensions.md
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Expand Up @@ -28,7 +28,7 @@ val twentySomethings = for (user <- userBase if (user.age >=20 && user.age < 30)

twentySomethings.foreach(name => println(name)) // prints Travis Dennis
```
The `for` loop used with a `yield` statement actually creates a `List`. Because we said `yield user.name`, it's a `List[String]`. `user <- userBase` is our generator and `if (user.age >=20 && user.age < 30)` is a guard that filters out users who are not in their 20s.
The `for` loop used with a `yield` statement usually creates the same sequence type as the first generator, here a `List`. Because we said `yield user.name`, it's a `List[String]`. `user <- userBase` is our generator and `if (user.age >=20 && user.age < 30)` is a guard that filters out users who are not in their 20s.

Here is a more complicated example using two generators. It computes all pairs of numbers between `0` and `n-1` whose sum is equal to a given value `v`:

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