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I want to extract the last four elements of a vector in DolphinDB. For example:

v=1..9
v[5:9]

Output:

enter image description here

I'd like to find an easier method to achieve this, so I tried the following method:

l=size(v)
v[l-4:l]

But the result is not as expected. Does anyone know how to solve this problem?

molddd123
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1 Answers1

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This is due to operator precedence. You need to add parentheses around 1-4:

l=size(v)
v[(l-4):l]

Or you can try a more efficient method:

v.tail(4)
carbonhydrate
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