StringReplacer

Replaces substrings matching a string or regular expression in the string contained in the source attribute.

Examples

In this example, a pure substitution of text is made without any use of regular expression functionality. This is the simplest kind of substring replacement.

Source String: Bobby

Text to Find: obb

Replacement Text: ill

Use Regular Expression: no

Case Sensitive: yes

Result: Billy

In this example, a pattern matching zero or more ’b’ characters is replaced with nothing.

Source String: Bobby

Text to Find: b*

Replacement Text:

Use Regular Expression: yes

Case Sensitive: yes

Result: Boy

In this example, a pattern matching zero or more ’b’ characters followed by a y is duplicated in the result (prepended by hyphens)

Source String: Bobby

Text to Find: (b*y)

Replacement Text: --\1-\1

Use Regular Expression: yes

Case Sensitive: yes

Result: Bo--bby-bby

Usage Notes

See the StringSearcher transformer help for additional regular expression examples.
To replace pairs of substrings, use the StringPairReplacer transformer.
To search for regular expression matches in a string without doing any replacement, use the StringSearcher transformer.
Test regular expressions with the Regular Expression Editor in the parameter menu.
For more information on regular expression syntax, see https://perldoc.perl.org/perlre#Regular-Expressions.

Configuration

Parameters

General

Attributes

This parameter specifies which attributes will have substrings replaced.

Mode

This parameter specifies whether the Text To Replace parameter specifies a regular expression or text pattern to search for.

Case Sensitive

Yes: The transformer will perform case-sensitive substring matching.
No: The transformer will perform case-insensitive substring matching.

Text to Replace

This parameter specifies the string or regular expression that will be replaced if it is found in an attribute value.

Replacement Text

The Replacement Text parameter specifies the substring that will replace instances of the Text To Replace parameter.

If replacement text contains \#, where # is a digit between 1 and 9, then it is replaced in the substitution with the portion of string that matched the n-th parenthesized subexpression of the regular expression.

Special character sequences can be used in both the Text to Replace and Replacement Text parameters.

If the Mode parameter is set to Replace Regular Expression, Advanced Regular Expressions (AREs) are supported. An ARE is one or more branches, separated by "|", matching anything that matches any of the branches.

This table lists the special characters:

Special Character	Description
\|	separates "branches" (or choices)
*	a sequence of 0 or more matches of what precedes it
+	a sequence of 1 or more matches of what precedes it
?	a sequence of 0 or 1 matches of what precedes it
.	matches any single character
^	matches the start of the value
$	matches the end of the value
[ ]	enclose a set of character choices
( )	enclose a "subexpression"
a	any character can be listed to be matched

Characters can be expressed as regular characters but they can also include any number of control characters.

Special character sequences are interpreted as shown below:

Sequence	Description
Ctrl+Shift+h (^H)	Backspace (0x08)
Ctrl+Shift+l (^L)	Form feed (0x0c)
Ctrl+Shift+j (^J)	Newline (0x0a)
Ctrl+Shift+r (^M)	Carriage return (0x0d)
Ctrl+Shift+i (^I)	Tab (0x09)
Ctrl+Shift+k (^K)	Vertical tab (0x0b)

Defining Special Characters

You can define special characters through the Text Editors. Click Open Text Editor from the parameter menu:

Text Editor

Enter characters using the shortcuts from the table above.

Note To see tab characters, click the Options menu on the bottom left and select Show Spaces/Tabs.

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.

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