Problem 645. Getting the indices from a vector

Created by Doug Hull

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","targetMode":"","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","targetMode":"","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>This is a basic MATLAB operation. It is for instructional purposes.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>---</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>You may already know how to</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/matlabcentral/cody/problems/640-do-a-binary-comparison-on-a-vector\"><w:r><w:t>find the logical indices</w:t></w:r></w:hyperlink><w:r><w:t> of the elements of a vector that meet your criteria.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>This exercise is for finding the index of indices that meet your criteria. The difference is this:</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[     vec = [11 22 33 44];\n  thresh = 25;\n      vi = (vec > thresh)\n\nvi =\n\n     0     0     1     1]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>What we are looking for now is how to get the values</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[   x =\n\n     3     4]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Because those are the indices where the binary comparison is true.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Check out</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/help/techdoc/ref/find.html\"><w:r><w:t>find</w:t></w:r></w:hyperlink><w:r><w:t>.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Given a vector, vec, return the indices where vec is greater than scalar, thresh.</w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

13467 Solutions
7606 Solvers

Last Solution submitted on May 27, 2023

Last 200 Solutions

Problem Comments

5 Comments

5 Comments

Show 2 older comments

goc3 on 18 Nov 2016

I added six more test cases.

Nguyen Huu Hung on 14 Sep 2019

hay

Kerem Kutan on 12 Jun 2020

kinda easy

Miriam Sánchez Fernández on 7 Nov 2020

It's easy with function "find"

Benjamin Hoehne on 1 Dec 2020

use "find"

Solution Comments

Show comments

Problem Recent Solvers7606

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 645. Getting the indices from a vector

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers7606

Suggested Problems

More from this Author51

Problem Tags

Community Treasure Hunt

Problem 645. Getting the indices from a vector

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers7606

Suggested Problems

More from this Author51

Problem Tags

Community Treasure Hunt

Players