You might want to pad your data with zeros to make sure it's of a certain length.  This could come in handy when sorting string data or for making the output look more consistent.  Another potential use case is if the system reading the export file requires specific fields to be a fixed length.

For example, you may have a variant barcode field with varying lengths, but the system ingesting the file requires that this field be a fixed 10-character field.

You can use the zfill() method in EZ Exporter to automatically add zeros in front of the string to ensure it's of the specified length.

For example, if the variants.barcode field has this value: 12345

Using this formula:

{{ variants.barcode }}.zfill(10)

Will output: 0000012345

As you can see here, this method automatically added 5 zeros in front of the string to make sure that the total number of characters is 10.