For example, let’s say that there is a vector vec, and we want to compare every element in the vector to 5 to determine whether it is greater than 5 or not. Relational operators can be used with vectors and matrices. 2.5.1 Relational Expressions with Vectors and Matrices Logical vectors use relational expressions that result in true/false values. Stormy Attaway, in Matlab (Third Edition), 2013 2.5 Logical Vectors The built-in function isequal also accomplishes this: In MATLAB, using the equality operator with arrays will return 1 or 0 for each element the all function could then be used on the resulting array to determine whether all elements were equal or not. The function isequal is useful in comparing arrays. For example:įor both vectors and matrices, an empty vector will be returned if no elements match the criterion. For example, to find all of the elements in a vector that are greater than 5:įor matrices, the find function will use linear indexing when returning the indices that meet the specified criteria.
The function find returns the indices of a vector that meet the given criteria. Here are some examples.įor the following variable vec2, some, but not all, elements are true consequently, any returns true but all returns false. The function all returns logical true only if all elements represent true. The function any returns logical true if any element in a vector represents true, and false if not. There are built-in functions in MATLAB which are useful in conjunction with logical vectors or matrices two of these are the functions any and all. To create a vector or matrix of all logical 1s or 0s, the functions true and false can be used.īeginning with R2016a, the ones and zeros functions can also create logical arrays directly. So, type casting the variable v would work: Only logical 1s and 0s can be used to index into a vector. The difference between the vector in this example and isg is that isg is a vector of logicals ( logical 1s and 0s), whereas by default is a vector of double values. Subscript indices must either be real positive integers or logicals. For example, if only the elements from the vector that are greater than 5 are desired: This logical vector can be used to index into the original vector. What we have done is to create a logical vector isg. To determine how many of the elements in the vector vec were greater than 5, the sum function could be used on the resulting vector isg: Although the result is a vector of ones and zeros, and numerical operations can be done on the vector isg, its type is logical rather than double. Note that this creates a vector consisting of all logical true or false values. The result would be a vector (with the same length as the original) with logical true or false values.
For example, let's say that there is a vector vec, and we want to compare every element in the vector to 5 to determine whether it is greater than 5 or not. 2.4.1 Relational Expressions with Vectors and Matrices Stormy Attaway, in Matlab (Fourth Edition), 2017 2.4 Logical Vectors
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