How to Use Expressions and Pega 7 Library Functions for String Manipulations in a Data Transform or Activity

For this post, Pega 7.1.9 was used. Pega 7 (and earlier versions) provides several utility functions for manipulating Strings.
These functions can be called as part of Expressions in Data Transforms and Activities.

Summary

  1. Sample Data Transform and Debugging
  2. Examples of String Manipulations with Expressions and Functions
    1. Conversion to Upper- and Lower Case
    2. Extraction of Substrings
    3. String Comparison
    4. Substring Search
    5. Substring Replace
    6. String to Number Conversions

Related Posts

  • For this example, a data transform with 7 input parameters was created:

Data Transform - TransformNames - Parameters Tab

  • On the Definition tab, the Set action is used to assign new values to the parameters using expressions. Here, Param.fullName is set using concatenation and conversion to upper case.

Data Transform - TransformNames - Set Action and Expression Builder Gear Icon

Data Transform - TransformNames - Pega 7.1.9 Expression Builder

  • The data transform can be run by clicking on Actions > Run.
  • Use the Trace button to start the Tracer. This allows to view the transformed input parameter values.

Data Transform - TransformNames - Run Data Transform Page

  • The data transform’s execution page can be viewed by clicking on the FIRST row in the Tracer (…execution page state after running the data transform).

Data Transform - TransformNames - Run Data Transform - Steps Execution and debugging in Tracer

  • Click on the =unnamed= link in the Parameter Page Name row to open the parameter page.

Data Transform - TransformNames - Tracer Debugging - View Trace Event

  • Here, the parameter page shows the data transform’s parameters AFTER execution is completed.

Data Transform - TransformNames - Tracer Debugging - View Data Transform Parameter Page

  • The Pega 7 String Library functions use the methods of the java.lang.String class. But, NOT ALL methods of java.lang.String are included in the Pega 7 String library.

A: Conversion to Upper- and Lower Case

  • Changing the case of a String is straightforward. Here, a single input String is converted to upper case.
    @String.toUpperCase(Param.firstName)
    "ULYSSES"
  • Likewise, a method exists for changing the case of a single input String to lower case.
    @String.toLowerCase("Ulysses S. Grant")
    "ulysses s. grant"
  • The + operator can be used for concatenating multiple parameters to one input parameter:
    @String.toLowerCase(Param.firstName + " " + Param.middleName + ". " + Param.lastName)
    "ulysses s. grant"

B: Extraction of Substrings

  • There are two overloaded @String.substring methods (same name, different input parameters) that can be used to extract a substring from a given string. The first one has 3 input parameters, the string (zero indexed) and a start-(inclusive) and end index (exclusive) and uses to the Java method substring(int beginIndex, int endIndex).
    @String.substring("304-678-9185 EXT 776", 0, 12)
    "304-678-9185"
  • To extract the last 4 digits of the phone number:
    @String.substring("304-678-9185 EXT 776", 8, 12)
    "9185"
  • The second substring method only has 2 input parameters, the string and the start index.
  • To extract the extension in this example, use:
    @String.substring("304-678-9185 EXT 776", 17)
    "776"
  • The result of a function can be passed as an input parameter to another function. Here, the 10-digit phone number is extracted first. Then, the area code is extracted:
    @String.substring(@String.substring("304-678-9185 EXT 776", 0, 12), 0, 3)
    "304"
  • @String.length is used to obtain the length of a given string, i.e. the number of characters:
    @String.length("Blueberry")
    9

C: Comparison

  • @String.equalsIgnoreCase is used to compare two Strings (case-insensitive). For example:
    @String.equalsIgnoreCase(Param.firstName, Param.lastName)
    false
  • @String.notEqualsIgnoreCase is used to compare two Strings for INEQUALITY. For example:
    @String.notEqualsIgnoreCase(Param.firstName, Param.lastName)
    true
  • @String.equals is used for CASE-SENSITIVE comparison:
    @String.equals("Blue", "blue")
    false
  • @String.notEquals is used for CASE-SENSITIVE comparison for INEQUALITY:
    @String.notEquals("Blue", "blue")
    true

D: Substring Search

  • @String.contains is used to search for the occurrence of a given substring within a string:
  • Here, Param.street is "Oak Hill Dr" and the method is used to check if it contains "Hill".
    @String.contains(Param.street, "Hill")
    true
  • @String.pxContainsViaRegex is used to search for the occurrence of a given substring within a string using a regular expression. For details on regular expressions, see the java.util.regex.Pattern class documentation.
  • In this example, a regular expression, \d{3}-\d{3}-\d{4}, is used to search for 10-digit phone numbers in a given String. Note that the \ character needs to be escaped as per Java syntax, using \\.
    @String.pxContainsViaRegex("phone=345-444-0001|name=smith", "\\d{3}-\\d{3}-\\d{4}", true)
    true
  • @String.startsWith is used to check if a string starts with a given substring.
  • @String.endsWith is used to check if a string ends with a given substring:
    @String.endsWith(Param.street, "Dr")
    true
  • @String.indexOf can be used to get the start index of a substring within a given String.
    @String.indexOf(Param.street, "Hill")
    4
  • If the given substring is NOT found, @String.indexOf returns -1, for example:
    @String.indexOf("Oak Hill Dr", "Blvd")
    -1
  • @String.indexOf is often used with @String.substring.
  • For example, Param.inputRow is "Name=Warren". To extract the actual name:
    @String.substring(Param.inputRow, @String.indexOf(Param.inputRow, "=") + 1)
    "Warren"

E: Substring Replace

  • @String.replaceAll is used to replace all occurrences of a given string with another string.
  • In this example, all of the hyphen characters are replaced with pipe characters:
    @String.replaceAll("apple-banana-cherry-date", "-", "|")
    "apple|banana|cherry|date"
  • @String.pxReplaceAllViaRegex is used to replace all substrings that match the given regular expression. For details on regular expressions, see the java.util.regex.Pattern class documentation.
  • For example, to replace all 10-digit phone numbers in a String with XXX-XXX-XXXX:
    @String.pxReplaceAllViaRegex(
    "Mr.Smith's work phone number is 675-999-0017 and his cell phone is 778-000-9999.",
    "\\d{3}-\\d{3}-\\d{4}",
    "XXX-XXX-XXXX")
    "Mr.Smith's work phone number is XXX-XXX-XXXX and his cell phone is XXX-XXX-XXXX."

F: String to Number Conversions

  • @String.isInteger is used to validate that a given String represents a number of type Integer:
    @String.isInteger("178")
    true
  • @String.isDouble is used to validate that a given String represents a number of type Double:
    @String.isDouble("199.49")
    true
  • Strings that represent Integer and Double type numbers can be converted to Integer and BigDecimal Java types:
    @String.toInt("149")
    149
  • If the String does not contain a valid Integer value, the function returns 0.
    @String.toInt("99.99")
    0
  • @String.toDecimal supports thousands separators and a decimal point:
    @String.toDecimal("1,250,599.39")
    1250599.39

Leave a Reply