@cifirst |

Index of the first non-missing value in each column of a matrix.

Syntax: @cifirst(m)

m: matrix

Return: vector

Returns a vector containing the index (i.e, row number) of the first non-missing value of each column of the matrix m.

Examples

Let M1 be an lower triangular matrix whose elements above the main diagonal are NAs. In this case,

= @cifirst(m1)

returns a column vector whose elements are the integers 1, 2, ..., .

Cross-references