> For the complete documentation index, see [llms.txt](https://docs.apica.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apica.io/platform-docs/test-data-orchestrator-tdo/user-documentation/api-guide/assignment-rule-apis/create-assignment-rule/using-the-format-function-in-an-assignment-rule.md).
# Using the FORMAT Function in an Assignment Rule
When you want to assign a value using the FORMAT function (e.g., assign the current date to a date field in a specific format) you need to add the ‘function’ parameter to the ‘operand’ section of the message, and then the actual formatting string in the ‘value’ section.
```
{
"context": {
"user": "user_ID",
"password": "XXXX",
"project": {
"name": "imp_payments_demo",
"version": "1.0"
},
"workSet": {
"name": "api_2_workset",
"version": "1.1"
}
},
"entity": {
"step": {
"name": "imp_enter_details",
"version": "1.0"
},
"attribute": "test_string",
"operands": [
{
"operator": "ASSIGN",
"function": "FORMAT",
"value": "%D|yyyy-MM-dd"
}
]
}
}
```
The return message will include the information on the rule that you created.
Return message using FORMAT function
In TDO, you can now see the rule that you created.