August 17, 2023

tReplaceList – Docs for ESB 5.x

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tReplaceList

tReplaceList_icon32_white.png

tReplaceList Properties

Component family

Data Quality

  

Function

Carries out a Search and Replace operation in the input columns
defined based on an external lookup.

Purpose

Helps to cleanse all files before further processing.

Basic settings

Schema and Edit
schema

A schema is a row description, it defines the number of fields to be processed and
passed on to the next component. The schema is either Built-in or stored remotely in the
Repository.

Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.

Two read-only columns, Value and Match are added to the output
schema automatically.

Warning

The data Type defined in the schemas must be
consistent, ie., an integer can only be replaced by another
integer using an integer as a look up field. Values of one
type cannot be replaced by values of another
type.

 

 

Built-in: The schema will be
created and stored locally for this component only. Related topic:
see Talend Studio User Guide.

 

 

Repository: The schema already
exists and is stored in the Repository, hence can be reused in
various projects and job designs. Related topic: see
Talend Studio User
Guide.

 

Lookup search column

Select the column to be searched in the lookup schema.

 

Lookup replacement column

Select the column where the replacement values are stored.

 

Column options

Select the columns of the main flow where the replacement is to be
carried out.

Advanced settings

tStat
Catcher
Statistics

Select this check box to collect log data at the component
level.

Global Variables

ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.

A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl +
Space to access the variable list and choose the variable to use from it.

For further information about variables, see Talend Studio
User Guide.

Usage

tReplaceList is an intermediary
component. It requires an input flow and an output component.

Scenario: Replacement from a reference file

The following Job searches and replaces a list of states with their corresponding
two-letter codes. The relevant codes are taken from a reference file placed as lookup
flow in the Job.

Use_Case_tReplaceList1.png

Setting up the Job

  1. Drop the following components from the Palette onto the design workspace: two tFileInputDelimited components, a tReplaceList and a tLogRow.

  2. Connect the two tFileInputDelimited
    components to the tReplaceList component
    using Row > Main connections. Note that the link between the reference
    input component (the second tFileInputDelimited) and the tReplaceList component appears as a lookup row.

  3. Connect the tReplaceList component to the
    tLogRow component using a Row > Main
    connection.

Configuring the components

  1. Double-click the first tFileInputDelimited component to open its Basic settings view and set the parameters of the
    main input flow, including the path and name of the file to read and the
    number of header rows to skip.

    Use_Case_tReplaceList3.png

    In this example, the main input file provides a list of people names and
    US state names. The following shows an extract of the file content:

  2. Click the […] button next to Edit schema to open the [Schema] dialog box and set the input schema.

    According to the structure of the main input file, the input schema should
    contain two columns: name and
    state.

    use_case_treplacelist3-input_schema.png

    When done, click OK to close the dialog
    box and propagate the changes to the next component.

  3. Define the properties of the second tFileInputDelimited component similarly.

    Use_Case_tReplaceList4.png

    In this example, the reference input file provides a list of states and
    their two-letter codes. Accordingly, the reference input schema should have
    two columns: state and code.

  4. Double-click the tReplaceList component
    to open its Basic settings view to set the
    operation to carry out.

    Use_Case_tReplaceList2.png

  5. From the Lookup search column list,
    select the column to be searched. In this use case, we want to carry out a
    search on the state column.

  6. From the Lookup replacement column list,
    select the column containing the replacement values,
    code for the two-letter state codes in this
    example.

  7. In the Column options table, select
    Replace check box for the
    states column, to replace the state names with
    their corresponding codes.

  8. In the tLogRow component, select the
    Table check box for a better
    readability of the output.

Executing the Job

  • Save the Job and press F6 to execute
    it.

    Use_Case_tReplaceList6.png

    The state names have been replaced with their respective two-letter codes.

Document get from Talend https://help.talend.com
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Docs 5.x
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