# Curly braces, square brackets, parenthesis? **URL:** \ **Category:** Ignition\ **Created:** [June 29, 2023, 11:41pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746 "2023-06-29T23:41:37Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 29, 2023, 11:41pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/1 "2023-06-29T23:41:37Z")
Is there a guide somewhere for what to use when and where? I have a script calling a named query, it works if I type in a value for the parameter. I can't get the formatting right to pass a value from a tag. ---
**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\ **Post date:** [June 29, 2023, 11:55pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/2 "2023-06-29T23:55:20Z")
When you say a script, do you mean a project script or a binding on a property? In the majority of cases you will encase it in `{}`, ie `{[System]Client/User/Country}`. In python scripts you encase the path in `"`, ie `tagPath = "[System]Client/User/Country"` If you are calling it in a binding, and have it set as a query binding, select the parameter you want to use a tag to source and then press the little tag icon next to the parameters area ![Untitled](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/e/ce1e7d2707c54e0e153f42ff499accaeaa239b5a.png) It should auto fill with the expected format. ![Untitled2](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/6/065a14785754922834d126a82ce6890506ca3bd6.png) If you are in an actual python script and calling `system.db.runNamedQuery` and trying to bring the value from a tag, you will need to make a call to `system.tag.readBlocking(["TagPathHere"])` and put the result into a dictionary where the keys match the names of the parameters for the named query. ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 12:01am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/3 "2023-06-30T00:01:21Z")
I'm trying to call a named query from a button in Perspective. I'll post the script tomorrow when I have access to the gateway and designer again. thanks for the response. ---
**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\ **Post date:** [June 30, 2023, 12:20am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/4 "2023-06-30T00:20:35Z")
Then you are most likely in a python script. The following code should give you an idea of the general flow you should follow. ```auto tagPaths = [ "[provider]Path/To/Tag1", "[system]Path/To/Tag2" ] response = system.tag.readBlocking(tagPaths) value1 = response[0].value value2 = response[1].value queryResult = system.db.runNamedQuery("pathToQuery", {"param1": value1, "param2": value2}) self.session.custom.key=queryResult ``` ---
**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\ **Post date:** [June 30, 2023, 12:27am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/5 "2023-06-30T00:27:51Z")
> [@ryan.white](#): > > ```python > response = system.tag.readBlocking(tagPaths) > > value1 = response[0].value > value2 = response[1].value > > ``` You can also use the one-liner: ```python value1, value2 = [qval.value for qval in system.tag.readBlocking(tagPaths)] ``` ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [June 30, 2023, 6:34am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/6 "2023-06-30T06:34:33Z")
In scripts (actual scripts, not expressions), the language is jython (pretty much python running on java). There, the symbols are... python symbols. You can easily find a reference guide online, but basically: Parenthesis: used either for a function definition/call, ie `function_name(parameters/arguments)` or for tuples: `days_of_the_week = ('monday', 'thursday', 'wednesday', [...])`. They can also be used for 'scoping' when indentation annoys you. For example `some_list = get_items().filter().sort().reverse()` could be written ```python some_list = ( get_items() .filter_it() .sort_it() .reverse_it() ) ``` or ```python long_string = ( "long line of text" " and another one" " that will be concatenated" ) ``` Which wouldn't work without the parentheses. Square brackets are used for accessing values in data structures, for example `some_list[3]` will access the fourth element in the list (indexing is zero-based), `some_dict['key']` will access the `key` element in a dictionary... They can also be used to make lists: `[1, 2, 3, 4]` will create a list with those 4 elements. You'll often see brackets surrounding expression like this `[x*2 for x in range(12)]`. This is called a list comprehension. What's inside is a generator expression, and the results it yields are used to create a list. It's equivalent to `list(x*2 for x in range(12))` Curly braces are _pretty much_ the equivalent of brackets, but for dictionaries or sets. `{1, 2, 1, 3, 1, 4, 2, 3}` will create a set containing 1, 2, 3, 4. `{'name': "foo", 'value': 42}` will create a dictionary with the key/value pairs `name = foo` and `value = 42` Can be used in comprehensions just like brackets for lists. In expressions, parentheses are used for function calls. brackets are used to access data structure elements, for example `some_dataset[row_numer, column_name]` And curly braces, the ones you'll see the most, are used to note that the value inside is a path to a value defined somewhere else, and will be replaced by the value it references. {[default]some/path} will get the value of the tag `some/path` in the `default` tag provider. `{session.custom.foo}` will be the session custom property `foo`. `{view.parameters.bar}` will be the value of the parameter `bar` passed to the view. You'll get more details, use cases, etc in the inductive university. I highly encourage you to go through it. It takes a little while, because it has a lot to teach, but it's worth it. There's also the doc, which is frankly quite good. ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 11:16am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/7 "2023-06-30T11:16:51Z")
This works #Call Named Query to Delete Selected Recipe param = {"SelectedRecipeName":"junk"} system.db.runNamedQuery("Rec\_DeleteSelected",param) This doesn't def runAction(self, event): #SetUp Tag Variable Name varTag = ["[default]L8\_/Recipe/L8\_RecipeName"] #Read In Tag Value tagValue = system.tag.readBlocking(varTag) #Set Parameter Value for SelectedRecipeName To Use In Named Query param = {"SelectedRecipeName":tagValue} #Call Named Query to Delete Selected Recipe system.db.runNamedQuery("Rec\_DeleteSelected",param) ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 11:22am UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/8 "2023-06-30T11:22:49Z")
I see my missing step now! value0 = tagValue[0].value THANK Y'ALL! ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 12:32pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/9 "2023-06-30T12:32:06Z")
One more new issue but part of the same goal (recipes). /L8\_RecipeName is a string tag and the others are floats. I get the error " Error trying to coerce 'huh' to a number.". ```auto def runAction(self, event): #SetUp Tag Variable Name varTag = ["[default]L8_/Recipe/L8_RecipeName","[default]L8_/Recipe/L8_Rec_Ing1","[default]L8_/Recipe/L8_Rec_Ing2","[default]L8_/Recipe/L8_Rec_Ing3","[default]L8_/Recipe/L8_Rec_Ing4","[default]L8_/Recipe/L8_Rec_Ing5","[default]L8_/Recipe/L8_Rec_Ing6","[default]L8_/Recipe/L8_Rec_Ing7","[default]L8_/Recipe/L8_Rec_Ing8","[default]L8_/Recipe/L8_Rec_Ing7"] #Read In Tag Value tagValue = system.tag.readBlocking(varTag) #Reference Item value0 = tagValue[0].value value1 = tagValue[0].value value2 = tagValue[0].value value3 = tagValue[0].value value4 = tagValue[0].value value5 = tagValue[0].value value6 = tagValue[0].value value7 = tagValue[0].value value8 = tagValue[0].value value9 = tagValue[0].value #Set Parameter Value for SelectedRecipeName To Use In Named Query params = {"ParRecipeName":value0,"ParCloser":value1,"parFiller":value2,"ParJuicer":value3,"ParInfeedAuger":value4,"ParSpiral":value5,"ParSpiralInfeed":value6,"ParSiraldischarge":value7,"ParHopperShaker":value8,"ParInfeedCanBelt":value9} #Call Named Query to Save Recipe system.db.runNamedQuery("Rec_InsertData",params) ``` ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [June 30, 2023, 12:49pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/10 "2023-06-30T12:49:19Z")
Edit your post and wrap your code in triple backticks or use the preformatted text tool. This is hard to read. ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 1:33pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/11 "2023-06-30T13:33:30Z")
Sorry for my ignorance, no comprende ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [June 30, 2023, 1:34pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/12 "2023-06-30T13:34:15Z")
> [@eddie\_johnson](#): > > no comprende - Hit the pencil icon below each of your posts. - Select the code block. - Then press the \ button. ---
**Author:** ![eddie\_johnson](https://avatars.discourse-cdn.com/v4/letter/e/57b2e6/32.png) [@eddie\_johnson](https://forum.inductiveautomation.com/u/eddie_johnson)\ **Post date:** [June 30, 2023, 1:45pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/13 "2023-06-30T13:45:33Z")
I got it now. Y'alls help has been invaluable ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [June 30, 2023, 1:50pm UTC](https://forum.inductiveautomation.com/t/curly-braces-square-brackets-parenthesis/75746/14 "2023-06-30T13:50:00Z")
You're using the same value for every parameter. Clearly that's not what you meant to do ? Anyway, cleaned up version of that script, using values sequentially instead of always the same: ```python def runAction(self, event): tagPaths = [ "[default]L8_/Recipe/L8_RecipeName", "[default]L8_/Recipe/L8_Rec_Ing1", "[default]L8_/Recipe/L8_Rec_Ing2", "[default]L8_/Recipe/L8_Rec_Ing3", "[default]L8_/Recipe/L8_Rec_Ing4", "[default]L8_/Recipe/L8_Rec_Ing5", "[default]L8_/Recipe/L8_Rec_Ing6", "[default]L8_/Recipe/L8_Rec_Ing7", "[default]L8_/Recipe/L8_Rec_Ing8", "[default]L8_/Recipe/L8_Rec_Ing7" ] values = [qval.value for qval in system.tag.readBlocking(tagPaths)] keys = [ "ParRecipeName", "ParCloser", "parFiller", "ParJuicer", "ParInfeedAuger", "ParSpiral", "ParSpiralInfeed", "ParSiraldischarge", "ParHopperShaker", "ParInfeedCanBelt" ] params = dict(zip(keys, values)) system.db.runNamedQuery("Rec_InsertData", params) ```