1.冒号的作用
产生矢量，阵列标注以及for-loop迭代子
2.描述
冒号是MATLAB中最有用的操作符之一。它使用下述规则来创建有规则的空间矢量：
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j:k
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is the same as [j,j+1,...,k], or empty when j > k.
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j:i:k
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is the same as [j,j+i,j+2i, ...,j+m*i], where m = fix((k-j)/i), for integer values. For information on the definition of j:i:k with floating-point values, see Technical Solution 1-4FLI96. This syntax returns an empty matrix when i == 0, i > 0 and j > k, or i < 0 and j < k.
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如果你指定单标量阵列，MATLAB将j:i:k 解释为 j(1):i(1):k(1).
You can use the colon to create a vector of indices to select rows, columns, or elements of arrays, where:
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A(:,j)
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is the jth column of A.
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A(i,:)
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is the ith row of A.
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A(:,:)
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is the equivalent two-dimensional array. For matrices this is the same as A.
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A(:,j:k)
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is A(:,j), A(:,j+1),...,A(:,k).
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A(:,:,k)
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is the kth page of three-dimensional array A.
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A(i,j,k,:)
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is a vector in four-dimensional array A. The vector includes A(i,j,k,1), A(i,j,k,2), A(i,j,k,3), and so on.
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A(:)
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is all the elements of A, regarded as a single column. On the left side of an assignment statement,A(:) fills A, preserving its shape from before. In this case, the right side must contain the same number of elements as A.
注：上述内容来自于MATLAB帮助文档
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