# get\_attr
### Description
`get_attr` gives you access to named properties of an [instance](/guides/glossary/instance.md) using [expressions](/rule-language/expressions.md).
This is useful if the characteristics (properties) of an instance need to play a role in determining the next step in a [process](/guides/glossary/process.md).
If a property doesn’t exist, you can choose to have a default value assigned to it.
### Example
```
p is Person
get_attr(p, "age", 16) >= 18
```
atfinity dives in and looks up what the value of the attribute “age” is for the person in this [case](/guides/glossary/case.md). If “age” is 18 or higher, this condition evaluates to true.
If “age” has not been provided, or “age” is not even a property of a person, the default value ‘16’ will be used. This means the condition ‘greater than or equal to 18’ evaluates to false**.**
We can also use an expression to choose which property to access.
```
p is Person
get_attr(p, "favourite_property")
```
Here, the system takes what a user has entered as `favourite_property` to work with. If that property does not exist, the condition evaluates to ‘unknown’.
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