hi i started the matlab onramp course and im stuck on this further practice question i wld appreciate if anyone cld help me or even give an hint

[Shantanu Dixit]

hi areeb, can you elaborate what issue are you facing?

[Image Analyst]

That is not a question. It's just giving you information. For a demo of that, see the Answer below (scroll down) or show us the actual question.

[Sahas]

Hi @areeb,

From what I assume you may be trying this.

Answer 1

[Steven Lord]

As Image Analyst stated, it's an informational message not a question. Its intent is to let you know that the indices you use to index into an array in MATLAB need not refer to a contiguous section of the array. [They can, but they're not required to.]

x = (1:10).^2 % original array into which you want to index

x = 1x10

1 4 9 16 25 36 49 64 81 100

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contiguous = x([4 5 6]) % a section of x from the middle

contiguous = 1x3

16 25 36

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You can skip elements.

skip = x(1:2:end) % get every other element of x

skip = 1x5

1 9 25 49 81

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You can repeat elements.

repeated = x([3 5 5 7]) % 25 appears twice in the output

repeated = 1x4

9 25 25 49

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You can specify indices that aren't sorted.

unsorted = x([1 4 7 10 2:3:8 3 6 9]) % "shuffle" the elements

unsorted = 1x10

1 16 49 100 4 25 64 9 36 81

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In this last section I used the "skip" pattern as part of generating the unsorted list. I could have done that slightly more compactly by using it for all three sections.

unsorted2 = x([1:3:10 2:3:8 3:3:9]) % "shuffle" the elements

unsorted = 1x10

1 16 49 100 4 25 64 9 36 81

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[areeb]

OHHH i was forgetting () these

Answer 2

[Fangjun Jiang]

density=10:10:100

density = 1x10

10 20 30 40 50 60 70 80 90 100

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index=[1 3 6]

index = 1x3

1 3 6

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SelectedDensityValue=density(index)

SelectedDensityValue = 1x3

10 30 60

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