.. index::
   single: G7 Command; group
   single: G7 Command; listgroups
   single: G7 Command; glist

Groups of Sector Numbers
========================
	
We already have seen how, with the *add* and *do* commands, it is useful  to be able to specify a group of integers as arguments.  In the *lint*, *index*, and *ctrl* commands which we are about to explain, this concept of a group of integers is carried further.  For use in these commands, the group is specified first and then used in the commands.  *G7* has a dynamic group  that can be specified and respecified over and over as necessary.  It also can use the static groups as are defined in the *Fixer* program.  

The dynamic group is defined by the command:

**group <group definition>**
   Define the content of the dynamic group.  The sector numbers are specified as in the *add* command. 
      
   Example::

      group 19-25 (20 22)

   The name of this dynamic group is ':'.  The names and content of the static groups defined in *Fixer* are preceded by a ':' in the following commands.

Named groups also can be introduced with the *group* command.  The format is:

| **group <group name>**
|    **<group definition>**
|    This version of the *group* command adds a named group to the GROUPS.BIN file.  This group then can be used in other commands requiring group expressions by prefixing the group name with a colon ':'.  The group definition include a sequence of integers, a range of integers, a set of letters to specify spreadsheet columns, and other named groups.  To exclude a set of values from the group definition, simply include the set to be excluded in parentheses.

   For example::

      group Manufacturing   # All manufacturing sectors
      1-58
      f empmfg = @csum(emp, :Manufacturing)
      group NonchemicalMfg  # All manufacturing sectors except chemicals
      :Manufacturing (20-27)

**listgroups**
   List the names of all of the groups currently in the GROUPS.BIN file.

**glist <name>**
   List the sectors in a group.  The <name> specifies the group name.  
      
   After the above group command, the command ::

      glist :    

   would give the answer ::

      19 21 23 24 25

   If the *listgroups* command gives the answer ::

      Ag Min Mfg Trans Trade Util Serv

   Then ::

      glist Ag

   might, for example, give an answer like ::

      1  2  3  4