ArcGIS Python Toolbox Parameter Dependencies - python-2.7

I'm trying to connect two parameters. In the first, the user inputs a file which contains a list (each line is one item). In the second, I'm hoping to set a parameter of type Field or GPValueTable. Here's a look at how this part of the code currently looks like:
def getParameterInfo(self):
#Define parameter definitions
# Input Features parameter
in_features = arcpy.Parameter(
displayName="Input Features",
name="in_features",
datatype="DETextFile",
parameterType="Required",
direction="Input")
# User selection
selection_field = arcpy.Parameter(
displayName="Selection list",
name="selection_field",
datatype="Field",
parameterType="Required",
direction="Input")
selection_field.parameterDependencies = [in_features]
# Derived Output Features parameter
out_features = arcpy.Parameter(
displayName="Output Features",
name="out_features",
datatype="GPFeatureLayer",
parameterType="Derived",
direction="Output")
out_features.parameterDependencies = [in_features.name]
parameters = [in_features, selection_field]
return parameters
The text file looks like this:
A
B
C
The toolbox dialog output is just A. I'm having a hard time understanding what ArcGIS intended to create here. Perhaps I'm using the wrong data types, but their parameter explanation doesn't make it very clear.
Any ideas?

You are confused with the arcpy terminology, I think. The second parameter's datatype="Field" does not imply data can be read/parsed from a text file where the data columns are written, in fact it is the schema/fields of a proper table and expectation is not a simple text but the field objects of a table/feature class (in the toolbox's run-time, assignment to arcpy.Parameter yields a geoprocessing value object but it is a different discussion). If you look at the "Creating value table parameters" section here, GPFeatureLayer's (param0) fields are populated in param1 automatically when the dependency is set.
The solution is setting your selection_field to GPValueTable and populating the selection_field.filters[0].list by reading the in_features's content after the parameter is altered but has not validated in def updateParameters(...). Have a look at https://gis.stackexchange.com/questions/370250/updating-valuetable-parameter-of-arcpy-python-toolbox-tool.

Related

Terraform Splat Expression Giving "Invalid template interpolation value"

I am using data sources in Terraform to fetch a list of ids of my security groups as such:
data "aws_security_groups" "test" {
filter {
name = "group-name"
values = ["the-name"]
}
}
output "security_group_id" {
value = "The id is ${data.aws_security_groups.test.ids[*]}"
}
However, this is giving me the following error:
Error: Invalid template interpolation value
on main.tf line 11, in output "security_group_id":
11: value = "The id is ${data.aws_security_groups.test.ids[*]}"
|----------------
| data.aws_security_groups.test.ids is list of string with 1 element
Cannot include the given value in a string template: string required.
But if I use data.aws_security_groups.test.ids[0] instead it displays the ID.
Can someone help me to display the list of IDs?
First, I want to note that you don't necessarily need to combine this list with a string message at all if you don't want to, because Terraform will accept output values of any type:
output "security_group_ids" {
value = data.aws_security_groups.test.ids
}
If having them included as part of a bigger string is important for your underlying problem then you'll need to make a decision about how you want to present these multiple ids in your single string. There are various different ways you could do that, depending on what you intend to do with this information.
One relatively-straightforward answer would be to make the string include a JSON representation of the list using jsonencode, like this:
output "security_group_id_message" {
value = "The ids are ${jsonencode(data.aws_security_groups.test.ids)}"
}
If you want a more human-friendly presentation then you might prefer to use a multi-line string instead, in which case you can customize the output using string templates.
output "security_group_id_message" {
value = <<-EOT
The ids are:
%{ for id in data.aws_security_groups.test.ids ~}
- ${id}
%{ endfor ~}
EOT
}
Or, for an answer somewhere in between, you could use join to just concatenate the values together with a simple delimiter, like this:
output "security_group_id_message" {
value = "The ids are ${join(",", data.aws_security_groups.test.ids)}"
}
Note that I removed the [*] from your reference in all of these examples, since it isn't really doing anything here: data.aws_security_groups.test.ids is already an iterable collection, and so is compatible with all of the language features I used in the examples above.
IIRC the provider considers this ids attribute to be a set of strings rather than a list of strings, and so that [*] suffix could potentially be useful in other situations to force converting the set into a list if you need it to be typed that way, although if that is your intent then I'd suggest using one of the following instead so that it's clearer to a future reader what it does:
sort(data.aws_security_groups.test.ids) (if it being in lexical order is important to the behavior; Terraform uses lexical sorting by default anyway, but calling sort is a good prompt to a reader unfamiliar with Terraform to look up that function to see what the actual sort order is.)
tolist(data.aws_security_groups.test.ids) (functionally equivalent to sort above when it's a set of strings, but avoids the implication that the specific ordering is important, if all that matters is that it's a list regardless of the ordering)

Converting "Textarea" object from iPython wigdet to a list or iterable array

I have created several Textarea widgets in Jupyter/Python in order to capture some string inputs.
In the highlighted in yellow that you can see below, the idea is that the user puts a list of numbers here (copied from Excel) and later I need to convert this text into a list or an array that contains these numbers (an iterable object). I have no idea how to do this. See:
When I print the type of this object that is called "plus" I get this:
print(type(plus))
<class 'ipywidgets.widgets.widget_string.Textarea'>
But, I am expecting to have something like this:
plus = [454, 555]
Can I bounce some ideas off you to get this?
Thanks a lot!!!
If you have an ipywidget in general, you can observe its change and get its value as following.
foo = widgets.Textarea()
# to get the value
foo.value
# to do something on value change
def bar(change):
print(change.new)
foo.observe(bar, names=['value'])
You will then have to format the string you get from the products value, but that shouldn't be too difficult.
Hope this helps

Parse CSV efficiently in python

I am writing a CSV parser which has following structure
class decode:
def __init__(self):
self.fd = open('test.csv')
def decodeoperation(self):
for row in self.fd:
getcmd = self.decodecmd(row)
if cmd == 'A'
self.decodeAopt()
elif cmd == 'B':
self.decodeBopt()
def decodeAopt(self):
for row in self.fd:
#decodefurther dependencies based on cmd A till
#a condition occurs on any further row
return
def decodeBopt(self):
for row in self.fd:
#decodefurther dependencies based on cmd B till
#a condition occurs on any further row
return
The current code is working fine for me but I am not feeling good to iterate through the CSV file in all the methods. Could it be done in a better way?
There is nothing inherently wrong with using a common iterator across multiple methods, as long as you can determine in advance which method to dispatch to at any given point in the sequence (which you are doing by decoding the cmd from the row and getting 'A', 'B', etc.). The design has issues if you have to read several items before you could determine which method to call, and might have to back up if you picked the wrong method and needed to try another. In parsing, this is called backtracking. Since you are passing around a file object, backing up is difficult. Note that your separate decoder methods will have to know when to stop before reading the next row that contains a command, so they will need some sort of terminating sentinel row that they can recognize.
Some general comments on your Python and class design:
You have a nice simple if-elif-elif dispatch table that can translate to a Python dict like this:
# put this code in place of your "if cmd == ... elif elif elif..." code
dispatch = {
# note - no ()'s, we just want to reference the methods, not call them
'A': self.decodeAopt,
'B': self.decodeBopt,
'C': self.decodeCopt,
# look how easy it is to add more decoders
}
# lookup which decoder to use for the current cmd
decoder = dispatch[cmd]
# run it
decoder()
# or do it all in one line
dispatch[cmd]()
Instead of having your __init__ method open a file, let it accept an iterator object. This will make it much easier to write tests for your object, since you'll be able to pass simple Python lists containing CSV rows.
class decode:
def __init__(self, sequence):
self.fd = sequence
You might want to rename this var from 'fd' to something like 'seq', since it doesn't have to be a file, but could be any iterable that gives you decodable rows.
If you are doing your own CSV parsing, look at using the builtin csv module. It will do quite a bit of work for you, like parsing quoted strings that could contain commas, and can give you easy-to-work-with dicts for each row, given headers read from the input file, or specified by you. If you have modified __init__ as I suggested, you can use it like:
import csv
# assuming test.csv has a header row
reader = csv.DictReader(open('test.csv'))
# or specify headers if not - I encourage you to give these columns better names
reader.fieldnames = ['cmd', 'val1', 'val2', 'val3']
decoder = decode(reader)
decoder.decodeoperation()
Then you can write in decodeoperation:
cmd = row['cmd']
Note that this would impart a slightly different design to your class, that it would expect to be given a sequence of dicts, rather than a sequence of strings.

How to ensure that user can input any datatype (str, float, int, boolean...)?

So this is my first question on the forum and I hope I am doing it correct.
General question: How can I ensure that python does not return any errors when writing a script that allows the user to input values of different datatypes depending on the context or parameter they want to change?
More specific: I am new to python and want to write a script that allows users of The Foundry's Nuke to change values on multiple nodes of the same class at once. Depending on whether the desired parameter to change is a checkbox('bool'), and RGBA input ('4 floats')... the input has to be of a different type. Searching the forum I found that the type can be checked by type() function and compared in an if statement with the isinstance() function. I guess I could work with that, but the type of e.g. a Gradenode's multiply knob returns type 'AColor_Knob'. I expected something like float. And comparing it in an isinstance() does not give me a match regardless of the datatype I am comparing to.
Mainscript so far:
nukescripts.clear_selection_recursive()
userInput = nuke.getInput('Which type of nodes would you like to select? (!!!first char has to be capitalized!!!)',
'Shuffle')
matchingNodes = []
for each in nuke.allNodes():
if each.Class() == userInput:
matchingNodes.append(each)
else:
pass
for i in matchingNodes:
i.setSelected(True)
nuke.message(str(len(
matchingNodes)) + ' matching Nodes have been found and are now selected! (if 0 there either is no node of this type or misspelling caused an error!)')
userInput_2 = nuke.getInput('Which parameter of these nodes would you like to change? \n' +
'(!!!correct spelling can be found out by hovering over parameter in Properties Pane!!!)',
'postage_stamp')
userInput_3 = nuke.getInput('To what do you want to change the specified parameter? \n' +
'(allowed input depends on parameter type (e.g. string, int, boolean(True/False)))', 'True')
for item in matchingNodes:
item.knob(userInput_2).setValue(userInput_3)
How I checked the datatypes so far:
selected = nuke.selectedNode()
knobsel = selected.knob('multiply')
print(type(knobsel))
#if type(knobsel) == bool:
if isinstance(knobsel, (str,bool,int,float,list)):
print('match')
else:
print('no match')
You can call a TCL command with nuke.tcl(). In TCL, everything is a string, so type is irrelevant (in some commands).
p = nuke.Panel('Property Changer')
p.addSingleLineInput('class', '')
p.addSingleLineInput('knob', '')
p.addSingleLineInput('value', '')
p.show()
node_class = p.value('class')
knob_name = p.value('knob')
knob_value = p.value('value')
for node in nuke.allNodes(node_class):
tcl_exp = 'knob root.{0}.{1} "{2}"'.format(node.fullName(),knob_name,knob_value)
print tcl_exp
nuke.tcl(tcl_exp)
That should answer your question. There are many ways to approach what you're trying to do - if you want to keep it all in python, you can do type checking on the value of the knob. For example:
b = nuke.nodes.Blur()
print type(b.knob('size').value()).__name__
This creates a Blur node and prints the string value of the type. Although I don't recommend this route, you can use that to convert the value:
example = '1.5'
print type(example)
exec('new = {}(example)'.format('float'))
print type(new)
An alternative route to go down might be building yourself a custom lookup table for knob types and expected values.
Edit:
TCL Nuke Commands:
http://www.nukepedia.com/reference/Tcl/group__tcl__builtin.html#gaa15297a217f60952810c34b494bdf83d
If you press X in the nuke Node Graph or go to File > Comp Script Command, you can select TCL and run:
knob root.node_name.knob_name knob_value
Example:
knob root.Grade1.white "0 3.5 2.1 1"
This will set values for the named knob.

grails controller: access to parameter that has a list of elements

I need to access to items stored in a parameter that represents selected elements in a multiselect. I pass selected items from gsp to controller with the following code into the remoteFunction:
params: '\'receiptItemsSelected=\' + jQuery(this).val()'
Now, following the code found in discussion here, I use the closure to get each value, but if I perform a multiselect, the size of receiptItemsSelected is always 1, but value is, for example, 1,2. To get values as a list I've done the following in the controller
params.list("receiptItemsSelected")
but it does not give me two elements if I select two items in the multiselect, but always one element.
The question is: if I select two elements, how can I get each element and use it in the controller? And how can I have that elemnts as Long and not as String?
Thanks
If you're parameters are being passed with string representation of a list, e.g.:
http://yoursite.com/?receiptItemsSelected=1,2,3
You have to split the value using normal Groovy string manipulation and perform the type conversion yourself:
def receiptsAsLongs = params.receiptItemsSelected.split(',')*.toLong()
If your parameters are passed with the convention of repeated parameters makes a list, e.g.:
http://yoursite.com/?receiptItemsSelected=1&receiptItemsSelected=2
Then grails can convert this to a list for you using params.list(), but you must do the final String to Long conversion:
def receiptsAsLongs = params.list('receiptItemsSelected')*.toLong()
params.list() is intended for multi-valued parameters, i.e. it will work if you have
receiptItemsSelected=1&receiptItemsSelected=2
You may have more luck using serialize() rather than val() to build the request body.