matlab中的arrayfun,Matlab中arrayfun函数

arrayfun函数用于对数组中每个元素进行相同的函数操作。

例如，如果进行求平方操作。为避免循环，对于数组可以进行.^操作。即

a=rand(2,2); a2=a.^2;    %完成对数组a中每个元素的平方操作。

a=rand(2,2);b=rand(3,3);c=rand(4,4); 如果需要同时对a,b,c数组进行求平方操作。可以通过arrayfun实现 s(1).f1=rand(2,2);s(2).fl=rand(3,3);s(3).f1=rand(4,4);

y=arrayfun(@(x)(x.f1.^2),s,'UniformOutput',false)

以下是MATLAB帮助文档的几个例子。

% To run the examples in this section, create a nonscalar structure array with arrays of different sizes in field f1.

s(1).f1 = rand(3, 6);

s(2).f1 = magic(12);

s(3).f1 = ones(5, 10);

% Count the number of elements in each f1 field.

counts = arrayfun(@(x) numel(x.f1), s)

% The syntax @(x) creates an anonymous function. This code returns%

% counts =

% 18 144 50

% Compute the size of each array in the f1 fields.

[nrows, ncols] = arrayfun(@(x) size(x.f1), s)

% This code returns

%

% nrows =

% 3 12 5

% ncols =

% 6 12 10

% Compute the mean of each column in the f1 fields of s. Because the output is nonscalar, set UniformOutput to false.

averages = arrayfun(@(x) mean(x.f1), s, 'UniformOutput', false)

% This code returns

%

% averages =

% [1x6 double] [1x12 double] [1x10 double]

% Create additional nonscalar structures t and u, and test for equality between the arrays in fields f1 across structures s, t, and u.

t = s; t(1).f1(:)=0;

u = s; u(2).f1(:)=0;

same = arrayfun(@(x,y) isequal(x.f1, y.f1), s, t)

% This code returns

% same =

% 0 1 1

same = arrayfun(@(x,y,z) isequal(x.f1, y.f1, z.f1), s, t, u)

% This code returns

% same =

% 0 0 1