SubstringExtractor

Extracts a substring from the source attribute. The substring is taken from the range of characters specified.

Examples

To trim off the first character only, and extract the rest of the source string, use a start of 1 and an end of -1.
To trim off the last character only, and extract the rest of the source string, use a start of 0 and an end of -2.
To extract the second and third characters in the string, use a start of 1 and an end of 2.
To trim off a single character only, use a start of 4 and an end of 4.
If you want to split the four first characters of the string ABCDE, use four SubstringExtractor transformers and set their respective properties as follows:

0,0

1,1

2,2

3,3

Configuration

Parameters

General

Source String

Specify the attribute or other source for the string from which you want to extract a substring.

Start Index, End Index

Specify the position in the source string from which to begin extracting a substring, and the position in the source string to end the substring. Character indexes start at 0 for the first character. A negative index is used to indicate the position relative to the end of the string (-1 is the last character, -2 the second last, and so on).

If the last index is greater than or equal to the length of the string, then it is treated as if it were the end of the string. If the first index is greater than the last index, then an empty string is placed into the result attribute.

The index parameters may be entered as a number, or can be taken from the value of a feature attribute by selecting the attribute name from the pull-down list.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

How to Set Parameter Values

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.

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.

Content Types

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

Table Tools

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.

For more information, see Transformer Parameter Menu Options.

FME Community

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