# Fixed Length Parser

*Fixed Length Parser* processes a stream of fixed length data as an input and gives elements as parsed output. This is useful when the source data is in text format (information is contained in a single field) and it needs to be put into multiple fields for further integration.

## **Sample Use-Case**

The sample data that we are using is a Fixed-Length text file containing customers’ information.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FnheZ6ao4LaiGsB0cHrXT%2F0.png?alt=media)

Observe that all the information such as name, street number, street type, city, state, and zip code are concatenated in a single field. We want to parse the *Contact\_Details* field into *Name*, *Street Number*, *Street Type*, and other respective fields.

## **Extracting Data**

To parse the data, we first have to extract it.

Since the data is stored in a continuous stream, it can not be extracted directly using a *Fixed Length File Source* object. Therefore, we will use a combination of transformations to get the desired outcome. The diagram below explains the process that we’ll be following, right from extraction to parsing the data.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FPJpOwJ4Y9aa1mFSiE0ys%2F1.png?alt=media)

Let’s begin with extracting the data.

1. Go to *Toolbox > Transformations > Constant Value* and drag and drop the *Constant Value* object onto the designer.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2F0S7oZD8rvvWR1vh94iz2%2F2.gif?alt=media)

2. Right-click on the object’s header and select *Properties* from the context menu.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2Fe0OV3p8k6Zb7ku2n7bJL%2F3.png?alt=media)

3. In the *Constant Value* field, provide the file path of the source file (file containing customers' data in a stream). Click *OK*.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FqnQf57XEvr1nZO4WrdKB%2F4.png?alt=media)

4. Next, go to *Toolbox > Function Transformations > Files > ReadFileText(String filePath) - String*, and drag and drop the object onto the designer.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FVM1Tp6sxQieybUdHCXTH%2F5.jpeg?alt=media)

You can see that the dragged transformation object has two sub-nodes - *Input* and *Output.*

5. Expand the *Input* node and map the *Value* field from the *Constant Value Transformation* object to the *filePath* field inside the *Read File Text* object.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2F8HWsFwIVl7oalILSc9iX%2F6.gif?alt=media)

This will redirect Astera to read the data from the given file path. Now we can use the *Fixed Length Parser* object to parse the text data into separate fields.

## **Using Fixed Length Parser**

1. To get the *Fixed Length Parser* object, go to *Toolbox > Text Processors > Fixed Length Parser* and drag and drop the object onto the designer. Map the *Value* field, under the *Read File Text* object, onto the *Text* field inside the *Fixed Length Parser* object.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FSPOAGFeOq2oDmSa069pV%2F7.gif?alt=media)

You can see that the dragged-object also contains an *Output* sub-node which is currently empty.

2. Configure the *Fixed Length Parser* object by right-clicking on its header and selecting *Properties*.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FIAgNdhOIIQefcd5Bt9ra%2F8.png?alt=media)

3. A properties window will open. Here you will see three options, make sure the first two options are checked.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FOnJ6p2wlutglXaYVCgli%2F9.png?alt=media)

4. Click *Next*, and you will be directed to a *Source Fields* window.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FKC3UnoMBOygfUBk05Yoy%2F10.png?alt=media)

Here, you have to provide the name of each field that you want to parse the source data into, as shown below.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FAkTvJzV0SW7q2oHwTgZ8%2F11.png?alt=media)

5. Click *OK*. Now, expand the *Output* node inside the *Fixed Length Parser* object. You will see all the fields that you have created in the previous step.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2F1BvgPidRGctT6gEyB42N%2F12.png?alt=media)

6. Right-click on the object’s header and select *Preview Output* from the context menu.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FiXfPm94sBgdFxFXCFbgm%2F13.png?alt=media)

A *Data Preview* window will open. Expand the nodes, and you will see a parsed output of each record.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FRWgRyBcG11AnCvMvsDzF%2F14.png?alt=media)

To store this parsed output, write it to a destination file.

## **Writing to a Destination**

1. Right-click on the *Output* sub-node inside the *Fixed Length Parser* object, and go to *Write to > Excel Workbook Destination*. An *Excel Workbook Destination* object will be added to the dataflow designer with auto-mapped fields.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FB6hPIiCDQXlBqomjgB2O%2F15.gif?alt=media)

2. Configure settings for the [*Excel Workbook Destination*](https://documentation.astera.com/v/astera-data-stack-v8/dataflows/destinations/excel-workbook-destination) object.
3. Click on the *Start Dataflow* icon, located in the toolbar at the top, to create this destination file.

![](https://750977703-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqHxyVNGb7tSdIWecl6Ru%2Fuploads%2FKOSFefo85663qCv5PovP%2F16.png?alt=media)