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help for cgroup                                                  (Roger Newson)
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Group contiguous observations with identical values of a varlist

        cgroup varlist , generate(newvarname)


Description

    cgroup inputs a list of variables specified by a varlist, and generates,
    as output, a new integer-valued variable, indicating, in each
    observation, membership of a group of contiguous observations with
    identical values of the varlist.  It is therefore a non-sorting version
    of gsort.


Options

    generate(varname) is required, and specifies the name of an output
        variable to be generated.  This output variable will contain, in each
        observation, the group to which that observation belongs.  It will
        have 1 integer value per contiguous group of observations with
        identical values for the variables in the varlist, in ascending order
        of appearance in the dataset, starting with 1.


Examples

    The following example demonstrates the use of cgroup with the sencode
    package, downloadable from SSC.

        .sysuse auto, clear
        .gene firm=word(make,1)
        .cgroup foreign firm, gene(firmseq)
        .sencode firm, replace manyto1 gsort(firmseq)
        .tab firm, missing

    The following example demonstrates the use of cgroup with the group()
    function of egen.  Alternatively, we could have used the xgroup package,
    downloadable from SSC.

        .sysuse auto, clear
        .gene firm=word(make,1)
        .cgroup foreign firm, gene(firmseq)
        .egen firmord=group(firmseq foreign firm), label
        .tab firmord, m


Author

    Roger Newson, National Heart and Lung Institute, Imperial College London,
    UK.
    Email: r.newson@imperial.ac.uk


Also see

     Manual: [D] egen, [D] gsort
    On-line: help for egen, gsort
             help for sencode, xgroup if installed