# Custom Expression
The Custom Expression Editor, accessible by clicking on the "..." button, allows you to use advanced expressions for generating your values. You can use a wide range of functions and operators such as string functions, mathematical operations, logical expressions (if-else statements), and reference other columns in your dataset to create new and unique values.
## Faker Configuration
* **Expression**: Enter the custom expression to generate the data. For example, `If(Len([password]) > 10, True, False)`.
* **Add Suffix**: Enter any additional suffix to append to the generated data (optional).
* **Replace only if Non-Null**: Check this box to ensure that the faker only replaces non-null values in the column. If unchecked, it will replace all values, including nulls.
By configuring these options, you can tailor the custom expression faker to generate appropriate anonymized data for your specific column in DataFakery Studio, ensuring it meets your custom logic and requirements.
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