Problem 1203. Reference Index Number

Created by Nicholas Howe
Appears in Indexing II

Difficulty:Rate

Solve Later
Add To GroupÃ‚

Given a reference set R of elements (each unique but identical in type), and a list V of elements drawn from the set R, possibly with duplicates, return K such that R(K) == V. The elements of R may be numeric or string.

For example, refIndex(9:-1:5,[7 5 6 5]) should return [3 5 4 5].

Solve

Solution Stats

978 Solutions
267 Solvers

Last Solution submitted on Mar 11, 2025

Last 200 Solutions

Problem Comments

1 Comment

1 Comment

Nicholas Howe on 14 Jan 2013

Can this be done efficiently using regexp?

Solution Comments

Show comments

Group

Indexing II

22 Problems
160 Finishers

Getting the indices from a vector
Symmetry of vector
Calculate the Number of Sign Changes in a Row Vector (No Element Is Zero)
Count consecutive 0's in between values of 1
Find last zero for each column
Oh Zero Zero Zero!!!
Create an index-powered vector
Find nth maximum
Decimation - Optimized for speed
Unique values without using UNIQUE function
Symmetry of vector
Generate a vector like 1,2,2,3,3,3,4,4,4,4
Create an n-by-n null matrix and fill with ones certain positions
Implement a bubble sort technique and output the number of swaps required
Create a vector whose elements depend on the previous element
Set a diagonal
Unique values without using UNIQUE function
Generate a vector like 1,2,2,3,3,3,4,4,4,4
Change the sign of even index entries of the reversed vector
Decimation
Insert zeros into vector
Reference Index Number
Determine the number of odd integers in a vector
Max index of 3D array
Finding peaks
Getting the indices from a vector

Problem Recent Solvers267

Problem Tags

Community Treasure Hunt

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

Start Hunting!