# Evaluating strings in sparql
**URL:** https://community.stardog.com/t/evaluating-strings-in-sparql/335
**Category:** Support
**Created:** [May 19, 2017, 4:16pm UTC](https://community.stardog.com/t/evaluating-strings-in-sparql/335 "2017-05-19T16:16:56Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Samur\_Araujo](https://community.stardog.com/u/Samur_Araujo)
#### Post date: [May 19, 2017, 4:16pm UTC](https://community.stardog.com/t/evaluating-strings-in-sparql/335/1 "2017-05-19T16:16:56Z")
Hi all, is it possible to evaluate a string in sparql?
Example:
```auto
select ?value where {
?s foo:frequency ?a .
?s foo:formula ?formula.
bind( eval (?formula) as ?value)
}
```
Where the ?formula would be a string like this:
`?formula = "?a + 10"` (it is store in the database as a string)
I want to evaluate the expression `?a + 10` during execution time.
Is that functionality available?
Best,
---
### Author:  [@zachary.whitley](https://community.stardog.com/u/zachary.whitley)
#### Post date: [May 19, 2017, 4:36pm UTC](https://community.stardog.com/t/evaluating-strings-in-sparql/335/2 "2017-05-19T16:36:22Z")
Out of the box you can't do something like that but Stardog makes it easy to write user defined functions that could do something like that. See [this](https://github.com/stardog-union/stardog-examples/tree/develop/examples/function) example.
Your query would need to look a little bit different like the following:
> select ?value where {
> ?s foo:frequency ?a .
> ?s foo:formula ?formula.
> bind( myfunc:eval (?formula, ?a) as ?value)
> }
I was working on writing a user defined function that would execute javascript expressions that would be similar to this but haven't gotten around to finishing it. I might be motivated to finish it if it was something that you'd find useful 😉
PS I'm assuming you're looking for something generic and want to use some additional logic for selecting the formula and/or have a large number of formulas. You can evaluate basic arithmetic expressions directly in SPARQL.
---
### Author:  [@system](https://community.stardog.com/u/system)
#### Post date: [June 2, 2017, 4:36pm UTC](https://community.stardog.com/t/evaluating-strings-in-sparql/335/3 "2017-06-02T16:36:28Z")
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