Matlab中cellfun函數的使用

Compute the mean of each vector in cell array C.

C = {1:10, [2; 4; 6], []};

averages = cellfun(@mean, C)
This code returns

averages =
    5.5000    4.0000       NaN

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　　該函數就是專門對cell數組進行操作的，個人認為是代替了傳統的for循環，和C語言不一個思想，主要是行列化矩陣，一次處理。

　　比如a = {[1 2 3] [4 5 6]},那么cellfun(@length,a)得到6。線cell2mat也可以吧，然后分別計算，在累加。

Compute the size of each array in C, created in the previous example.

[nrows, ncols] = cellfun(@size, C)
This code returns

nrows =
     1     3     0
ncols =
    10     1     0

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　　cellfun中使用自定義函數對cell數組進行處理；既然可以自定義函數，那么cellfun中的的中間部分的參數個數和自定義函數需要的參數數目相同。

　　還能這么用。

queryNearestNeighborIds = cellfun( @(vector, index) vector(index), queryCandidateIds, queryNearestNeighborIds, 'UniformOutput', false );
	

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Create a cell array that contains strings, and abbreviate those strings to the first three characters. Because the output strings are nonscalar, set UniformOutput to false.

days = {'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'};

abbrev = cellfun(@(x) x(1:3), days, 'UniformOutput', false)
The syntax @(x) creates an anonymous function. This code returns

abbrev = 
    'Mon'    'Tue'    'Wed'    'Thu'    'Fri'