help mata mm_posof()
-------------------------------------------------------------------------------

Title

    mm_posof() -- Find element in vector


Syntax

        real scalar mm_posof(haystack, needle)

    where

              haystack:  transmorphic vector haystack
                needle:  transmorphic scalar needle


Description

    mm_posof() returns the position of the first occurrence of element needle
    in vector haystack, or 0 if needle does not occur.

    Note that mm_posof() is now outdated by the more flexible and faster
    mm_which() function.  (mm_posof() has been written before the appearance
    of the select() function Mata.)


Remarks

    mm_posof() may be used with numeric elements or with string elements. For
    example:

        : mm_posof(("one","two","three"),("two"))
        2
        
        : mm_posof((1,2,3),(3))
        3

    However:

        : mm_posof((1,2,3),("2"))
        0

    Furthermore:

        : mm_posof(("one","two","three"),("four"))
        0


Conformability

    mm_posof(haystack, needle)
    haystack: 1 x c or r x 1
      needle: 1 x 1
      result: 1 x 1.


Diagnostics

    mm_posof() returns 0 if the element types of needle and haystack are
    different.


Source code

    mm_posof.mata


Author

    Ben Jann, ETH Zurich, jann@soz.gess.ethz.ch


Also see