# To get the meaning of this syntax

**URL:** <https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421>\
**Category:** Ignition\
**Created:** [May 15, 2024, 11:35am UTC](https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421 "2024-05-15T11:35:27Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Selvapandiaraj\_A](https://avatars.discourse-cdn.com/v4/letter/s/67e7ee/32.png) [@Selvapandiaraj\_A](https://forum.inductiveautomation.com/u/Selvapandiaraj_A)\
**Post date:** [May 15, 2024, 11:35am UTC](https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421/1 "2024-05-15T11:35:27Z")

</div>

> {'m1':self.props.selection.data[0].MachineName}  
> i want to know the meaning of the [0] , because i want to pass parameters to named query but it says i have given too many parameters

---

<div class="post-metadata">

**Author:** ![Hayden\_Watson](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/hayden_watson/32/48792_2.png) [@Hayden\_Watson](https://forum.inductiveautomation.com/u/Hayden_Watson)\
**Post date:** [May 15, 2024, 11:45am UTC](https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421/2 "2024-05-15T11:45:39Z")

</div>

Presumably you could select multiple items, Ignition will then give this as a list of selected items. `[0]` will give you the first item, `[1]` will give the second item etc.

If you only select 1 item it will just have this first selection at `[0]`

---

<div class="post-metadata">

**Author:** ![djs](https://avatars.discourse-cdn.com/v4/letter/d/e47774/32.png) [@djs](https://forum.inductiveautomation.com/u/djs)\
**Post date:** [May 15, 2024, 12:55pm UTC](https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421/3 "2024-05-15T12:55:08Z")

</div>

`[0]` means that you are accessing an element of an _array_ (technically a _list_ in python) at index _0_. That means that (in the snippet) `data` is an _array_(list), at index 0 it has an _object_, and that object has a property named _MachineName_. The value of that property is the value assigned to the `'m1'` key in the _dictionary_ shown in the snippet.

---

<div class="post-metadata">

**Author:** ![djs](https://avatars.discourse-cdn.com/v4/letter/d/e47774/32.png) [@djs](https://forum.inductiveautomation.com/u/djs)\
**Post date:** [May 15, 2024, 12:59pm UTC](https://forum.inductiveautomation.com/t/to-get-the-meaning-of-this-syntax/90421/4 "2024-05-15T12:59:36Z")

</div>

Where is this snippet from? If your problem is with passing too many parameters to a named query, then I wouldn't expect "`[0]`" to be your problem. Post more of your code with more context and we might be able to help you.