Generate random numbers without repeating a value: Difference between revisions
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(→{{header|Wren}}: Added alternative implementation which simply shuffles the numbers.) |
(→{{header|Go}}: Added alternative implementation which simply shuffles the numbers.) |
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</pre> |
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<br> |
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Alternatively and far more efficiently, we can simply create a list of the required numbers and randomly shuffle them. Go has a standard library function for this which uses the Fisher-Yates (aka Knuth) shuffle. |
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<lang go>package main |
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import ( |
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"fmt" |
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"math/rand" |
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"time" |
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) |
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func main() { |
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rand.Seed(time.Now().UnixNano()) |
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numbers := make([]int, 20) |
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for i := 0; i < 20; i++ { |
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numbers[i] = i + 1 |
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} |
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for i := 1; i <= 5; i++ { |
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rand.Shuffle(20, func(i, j int) { |
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numbers[i], numbers[j] = numbers[j], numbers[i] |
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}) |
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s := fmt.Sprintf("%2d ", numbers) |
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fmt.Println(s[1 : len(s)-2]) |
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} |
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}</lang> |
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{{out}} |
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<pre> |
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19 12 11 1 3 14 7 20 2 18 4 10 9 5 8 6 15 13 16 17 |
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10 6 11 3 5 13 15 4 16 12 1 14 20 7 2 19 8 17 9 18 |
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4 14 17 15 1 6 12 11 2 3 19 10 9 18 7 13 8 20 16 5 |
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13 12 8 3 9 17 14 10 6 2 11 20 19 18 4 7 16 1 15 5 |
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</pre> |
</pre> |
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