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middleAsColumn: Return all but first and last element as a column vector
Given input A, return all but the first and last elements, arranged as a column vector. (I.e., all dimensions after the first s...

2 months ago

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Matrix indexing with two vectors of indices
Given a matrix M and two index vectors a and b, return a row vector x where x(i) = M(a(i),b(i)).

2 months ago

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Getting logical indexes
This is a basic MATLAB operation. It is for instructional purposes. --- Logical indexing works like this. thresh = 4...

2 months ago

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Reindex a vector
You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place th...

2 months ago

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Remove the two elements next to NaN value
The aim is to *remove the two elements next to NaN values* inside a vector. For example: x = [6 10 5 8 9 NaN 23 9 7 3 21 ...

2 months ago

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Set the array elements whose value is 13 to 0
Input A either an array or a vector (which can be empty) Output B will be the same size as A . All elements of A equal to 13...

2 months ago

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Get the elements of diagonal and antidiagonal for any m-by-n matrix
In the problem <http://www.mathworks.com/matlabcentral/cody/problems/858-permute-diagonal-and-antidiagonal Problem 858. Permute ...

2 months ago

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We love vectorized solutions. Problem 1 : remove the row average.
Given a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solution will be tested for ac...

2 months ago

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Replicate elements in vectors
Replicate each element of a row vector (with NaN) a constant number of times. Examples n=2, A=[1 2 3] -> [1 1 2 2 3 3] n=0...

2 months ago

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Generate N equally spaced intervals between -L and L
Given N and L, return a list of numbers (in ascending order) that divides the interval [-L L] into N equal-length segments. For...

2 months ago

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intersection of matrices
Given two matrices filled with ones and zeros, determine if they share a common row, column entry. These matrices are of identic...

2 months ago

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Return unique values without sorting
If the input vector A is [42 1 1], the output value B must be the unique values [42 1] The values of B are in the same order a...

2 months ago

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First non-zero element in each column
For a given matrix, calculate the index of the first non-zero element in each column. Assuming a column with all elements zero i...

2 months ago

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Getting the indices from a matrix
Inspired by Problem 645. Getting the indices from a matrix. Given a matrix A (or a vector), return the indices (always in row...

2 months ago

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Piecewise linear interpolation
Given an Mx2 vector and a row of M-1 integers, output a two column vector that linearly interpolates Y times between each succes...

2 months ago

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De-dupe
Remove all the redundant elements in a vector, but keep the first occurrence of each value in its original location. So if a =...

3 months ago

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Create a function handle that reverses the input arguments of another function handle
Given a function that takes two input arguments and returns one output, create another function handle that performs the same op...

4 months ago

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Two-output anonymous function?
Return a function handle that when applied to an input, it produces two outputs: the first is the same as the input, and the sec...

4 months ago

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First use of arrayfun() and anonymous function @(x)
Create an anonymous function using @(x) for a parabola equation for the given coefficients stored in s with s(1)x2 + s(2)x + s(...

4 months ago

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Operate on matrices of unequal, yet similar, size
You may want to add a vector to a matrix, implying that the vector is added to each column of the matrix. Or multiply a 3x4x5 ma...

4 months ago

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Permute diagonal and antidiagonal
Permute diagonal and antidiagonal For example [1 2 3;4 5 6;7 8 9] -> [3 2 1;4 5 6;9 8 7] WITHOUT diag function (and variable n...

4 months ago

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Reverse the elements of an array
Reverse the order of elements in an array: eg: input X = [ 1 2 3 ; 4 5 6 ; 7 8 9 ] o...

4 months ago

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Rotate input square matrix 90 degrees CCW without rot90
Rotate input matrix (which will be square) 90 degrees counter-clockwise without using rot90,flipud,fliplr, or flipdim (or eval)....

4 months ago

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Removing rows from a matrix is easy - but what about inserting rows?
Assume A is a 5-by-5 matrix. A([2,4],:) = [] is a quick way to remove rows 2 and 4. Can you find a quick way to insert rows into...

4 months ago

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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

4 months ago

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Set some matrix elements to zero
First get the maximum of each *row*, and afterwards set all the other elements to zero. For example, this matrix: 1 2 3 ...

4 months ago

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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

4 months ago

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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

4 months ago

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Make an awesome ramp for a tiny motorcycle stuntman
Okay, given a vector, say v=[1 3 6 9 11], turn it into a matrix 'ramp' like so: m=[1 3 6 9 11; 3 6 9 11 0; 6 9 ...

4 months ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

4 months ago