# Iterate Using Expression **URL:** \ **Category:** Ignition\ **Created:** [March 3, 2022, 12:36am UTC](https://forum.inductiveautomation.com/t/iterate-using-expression/56755 "2022-03-03T00:36:28Z")\ **Posts on this page:** 1\ **Showing post:** 7
**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\ **Post date:** [March 3, 2022, 12:09pm UTC](https://forum.inductiveautomation.com/t/iterate-using-expression/56755/7 "2022-03-03T12:09:14Z")
> [@jespinmartin1](#): > > I had heard that scripting if faster than expressions Not so. > [@Binding Transforms Best Practices](https://forum.inductiveautomation.com/t/binding-transforms-best-practices/24899/2): > > Seat of the pants answer with no performance testing to back it up: native transforms (ie, mapping) will be faster than expression transforms will be faster than script transforms “Native” transforms are executing as direct Java code in and out. Expressions have to be parsed and calculated in steps, so there’s more lookups and variable timing involved. Scripts will almost certainly be the slowest - we have to either grab or create a Python interpreter, compile the function you provide (we … However, iterating through a json file with 10 items in script is in the ms range of speed, I highly doubt performance is a concern with even 500 files of that size throughout a project. Unless you’re iterating through the files in the same script. --- _[View the full topic](https://forum.inductiveautomation.com/t/iterate-using-expression/56755)._