GXEXP class¶

class geosoft.gx.GXEXP¶

EXP objects are created from text strings that contain
C-like math to be applied to channels in a database.
It is used with the geosoft.gx.GXDU.math() function (see DU). See also
IEXP for applying math expressions to images (grids).
See also geosoft.gx.GXDU.math() applies expressions to the database

static create((GXContext)ctx, (GXDB)arg1, (str)arg2, (int)arg3) → GXEXP:¶

This method creates an EXP object.

Parameters:	ctx (`geosoft.gx.GXContext`) – The GX execution context arg1 (`geosoft.gx.GXDB`) – Database Object arg2 (str) – Expression using channel names arg3 (int) – Maximum size of expression after expanding all local variables (those with $ prefix).
Returns:	EXP Object
Return type:	`geosoft.gx.GXEXP`

New in version 5.0.0.

Note:

Expressions are strings that contain C-like math to be
applied to channels in a database.  For example, following
an expression:

   "@a = mag-64000; @b = gravity*100;
    $sRatio = @a/@b;
    MULT = @a *@b;"

Rules:

   ;  - terminates a sub-expression
   @  - prefix to a temporary name, which is a double precision
        floating point number to be used later in the same
        expression.
   $  - prefix to a local GX variable name.  Such names will be
        evaluated to the variable value at the time geosoft.gx.GXEXP.create()
        is called.

   All other tokens are assumed to be channel names.

static create_file((GXContext)ctx, (GXDB)arg1, (str)arg2) → GXEXP:¶

This method creates an EXP object from a file

Parameters:	ctx (`geosoft.gx.GXContext`) – The GX execution context arg1 (`geosoft.gx.GXDB`) – Database Object arg2 (str) – File name
Returns:	EXP Object
Return type:	`geosoft.gx.GXEXP`

New in version 5.0.0.

is_null() → bool¶

Check if the instance of geosoft.gx.GXEXP is null (undefined)

Returns:	True if this is a null instance of `geosoft.gx.GXEXP`, False otherwise.
Return type:	bool`

static null() → GXEXP¶

A null (undefined) instance of geosoft.gx.GXEXP

Returns:	A null `geosoft.gx.GXEXP`
Return type:	`geosoft.gx.GXEXP`