RandomNumberGenerator

Categories

Calculated Values

Strings

Generates a uniformly distributed random number.

The random number is x, where Minimum Value <= x <= Maximum Value.

Output Ports

Note: Feature order may change in relation to other output ports. Feature order per port is maintained.

Parameters

Specify the minimum value that can be generated.

Specify the maximum value that can be generated.

The random number will be rounded to the number of digits specified in the Decimal Places parameter.

Note that in general, when the Minimum Value and Maximum Value is specified in an exponential form (for example, "1.0e+25"), Decimal Places refers to the number of decimal places in the exponential form.

If Minimum Value or Maximum Value have more decimal places than the Decimal Places requested for the result, the actual minimum value used will be rounded up and the actual maximum value used will be rounded down to the requested decimal places. This is to ensure that the generated random number will always fall between the Minimum Value and the Maximum Value.

The name of the attribute to hold the generated number.

Usage Notes

RandomNumberGenerator generates random numbers using the Tcl rand() function. The numbers generated by this function may not be considered truly random, because rand() requires an initial seed value, which determines the sequence of numbers that is generated. There are no more than 2^31 possible random number sequences, and these sequences repeat after 2^31 times. The same seed value, used repeatedly, generates the same numbers. Additionally, the sequence, by design, never produces the same number twice in a row.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

String Functions

These functions manipulate and format strings.

Special Characters

 A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.
Date/Time Functions Date and time functions are available in the Text Editor.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters Create your own editable parameters.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

  • Add a row
  • Remove a row
  • Move current row up one
  • Move current row down one
  • Move current row to top
  • Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

  • Cut a row - delete and copy to clipboard
  • Copy a row to the clipboard
  • Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

 

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