Swift: Indirect access / mutable - swift

I need to go to a referenced structure:
class SearchKnot {
var isWord : Bool = false
var text : String = ""
var toNext = Dictionary<String,SearchKnot>()
}
When inserting, I need to update values in toNext dictionary. Because I want to avoid recursion, I do it in a loop. But there I need a variable which jumps from one toNext item to the other, able to change it.
var knots = toNext
...
let newKnot = SearchKnot()
knots[s] = newKnot
The last command only changes a local copy, but I need the original to be changed. I need an indirect access. In C I would use *p where I defined it as &toNext. But in Swift?

I found a solution. I remembered old pascal days. ;-)
I don't use the last reference, but the second last. Instead of
knots[s]
I use
p.knots[s]
For hopping to the next knot, I also use
p = p.knots[s]
and could use
p.knots[s]
again. Also p.knots[s] = newKnot works, because p is local not the entire term.

Related

Eliminate repetition in updating strings selected randomly within a state property

First, I'm very new to Swift, and coding in general. I'm trying to use the correct terminology, so I apologize if it makes no sense. Doing my best!
Ok, so there appears to be a lot of information/answers on ways to random select strings (or integers, etc) from an array without repetition. However, in my current application, I am not using an array (I kind of am but not directly related to the question). But rather a #State designation, in which the variable has an initial value (a string with a number and letter) and is later updated when a button is pushed. The string changes to a randomly selected string from my assets folder based on the file name, which will be the same word but with a different number and letter. What is the simplest way to keep from updating to strings that have already appeared?
Example of what the code looks like:
#State var relevantWord = "bird"
Button {
let randoNum = Int.random(in: 1...5)
let x = ["a", "b", "c", "d"]
let randoLet = x.randomElement()
relevantWord = "bird" + String(randoNum) + String(randoLet)
}
So, the relevantWord variable starts as "bird2c" for example, and each time the button is pushed, it will change to "bird3b" then "bird4a" etc. I just want to keep it from repeating and return nothing when the assets are depleted. Thanks!

SAPUI5 List Item context binding, get the next path

I have a table of list items (questions) and I want to be able to re-arrange them. See screenshot.
Currently, on the button down press, I can get the current binding context and I am getting that sequence property (001). What I want to be able to do is also be able to get the path of the next list items binding context (002 in this case).
Current code...
// Move Question Down
onQuestionMoveDown: function (oEvent) {
// Get binding context
var source = oEvent.getSource().getBindingContext("view");
var path = source.getPath();
var object = source.getModel().getProperty(path);
var currentQuestionSequence = object.Sequence;
MessageToast.show("Current # " + currentQuestionSequence);
}
Then once I have that I can sort my updates logic.
A possible solution could be that you have an order value on your model and you update that order when the user clicks on the button.
If the list is sorted by that value you will achieve what you're looking for.
The items should be bound to the table via list binding, and so the data set would be an Array, the path for each line will be like ".../itemSet/0, .../itemSet/1, ...". So possible solution could be:
function getNextItem(oItem){
var oContext = oItem.getBindingContext("view"), // assumpe the model name is view
sPath = oContext.getPath(),
sSetPath = sPath.substr(0, sPath.lastIndexOf("/")),
iMaxLen = oContext.getProperty(sSetPath).length,
iCurIndex = parseInt(sPath.substr(sPath.lastIndexOf("/")+1));
// If it's already reach to be bottom, return undefined
return iCurIndex < iMaxLen -1 ? oContext.getProperty(sSetPath + "/" + ++iCurIndex) : undefined;
}
Regards,
Marvin

Unable to set a javascript date object to a cell hidden by filter

I have a script which checks certain conditions to send reminders emails or sms to my clients. the only issues I'm finding is that if I try to write a cell that is hidden by a filter, the script executes but the data is not changed in any way.
I'll write a short version of the whole script:
function test(){
var nowTime = new Date();
var sheet = SpreadsheetApp.getActiveSpreadsheet();
var lastrow =sheet.getLastRow();
var lastcol =sheet.getLastColumn();
var fullData =cell.offset(0, 0,lastrow-
cell.getRow()+1,lastcol).getValues();
var cell = sheet.getRange("A2");
var i=0;
while (i<fullData.length){
var reminderType =0;
var row = fullData[i];
if (row[0] == 1) {sendreminder();cell.offset(i, 2).setValue(new Date());}
}
}
if for example the first column has hidden all the rows with 1 the script executes and sends all the reminders but ignore the setvalue(), if the rows are visible it works perfectly.
One solution can de to remove the filter but would be very annoying since we use the filter a lot and the script is triggered by time every 10 minutes so I would be working on the sheet and suddenly the filter get removed to run the script.
I have tried with cell.offset, getrange etc.. without any success ... Ideas?
EDIT: The problem seems to be only if I try to write a date if (row[0] == 1) {cell.offset(i, 1).setValue(new Date());}
For instance I'm writing another information (a number) in a different column and that cell gets updated.
The rest remain the same
here is a test sheet I created:
https://docs.google.com/spreadsheets/d/1-FNDGmvCc8nRFTG65Sj9L2RhGn8R3DtwR3llwBG5-FA/edit#gid=0
For now I added this code to save the state of the filter and reestablish it at the end. It's not really elegant and still add a lot of chances of something being messed up or the script failing but it's the less invasive solution I came out with. Does someone has a better one?
// at the beginning
if (sheet1.getFilter()){
var filterRange= sheet1.getFilter().getRange();
var filterSetting = [];
var i=0;
while (i<filterRange.getNumColumns()-1) {filterSetting[i]= sheet1.getFilter().getColumnFilterCriteria(i+1);sheet1.getFilter().removeColumnFilterCriteria(i+1);i++; }
}
// At the end
if (sheet1.getFilter()){
var i=0;
while (i<filterRange.getNumColumns()-1) {if (filterSetting[i]) sheet1.getFilter().setColumnFilterCriteria(i+1, filterSetting[i]);i++; }
}
Given the fact the problem is not writing in the hidden row as it was pointed out, the solution is to use the formatdate to format the value before writing it in the cell.
Not ideal either since regional formattings might prevent the script from working on different accounts but sure better solution than disabling the filters.
here is the code i needed to add:
var nowTime = new Date();
var timeZone = Session.getScriptTimeZone();
var nowTimeFormatted = Utilities.formatDate(nowTime, timeZone, 'MM/dd/yyyy HH:mm:ss');
any idea on how to improve this script or to solve the original problem without workarounds is appreciated :)

Roblox- how to store large arrays in roblox datastores

i am trying to make a game where players create their own buildings and can then save them for other players to see and play on. However, roblox doesn't let me store all the data needed for the whole creation(there are several properties for each brick)
All i get is this error code:
104: Cannot store Array in DataStore
any help would be greatly appreciated!
I'm not sure if this is the best method, but it's my attempt. Below is an example of a table, you can use tables to store several values. I think you can use HttpService's JSONEncode function to convert tables into strings (which hopefully can be saved more efficiently)
JSONEncode (putting brick's data into a string, which you can save into the DataStore
local HttpService = game:GetService("HttpService")
-- this is an example of what we'll convert into a json string
local exampleBrick = {
["Size"] = Vector3.new(3,3,3),
["Position"] = Vector3.new(0,1.5,0),
["BrickColor"] = BrickColor.new("White")
["Material"] = "Concrete"
}
local brickJSON = HttpService:JSONEncode(exampleBrick)
print(brickJSON)
-- when printed, you'll get something like
-- { "Size": Vector3.new(3,3,3), "Position": Vector3.new(0,1.5,0), "BrickColor": BrickColor.new("White"), "Material": "Concrete"}
-- if you want to refer to this string in a script, surround it with two square brackets ([[) e.g. [[{"Size": Vector3.new(3,3,3)... }]]
JSONDecode (reading the string and converting it back into a brick)
local HttpService = game:GetService("HttpService")
local brickJSON = [[ {"Size": Vector3.new(3,3,3), "Position": Vector3.new(0,1.5,0), "BrickColor": BrickColor.new("White"), "Material": "Concrete"} ]]
function createBrick(tab)
local brick = Instance.new("Part")
brick.Parent = <insert parent here>
brick.Size = tab[1]
brick.Position= tab[2]
brick.BrickColor= tab[3]
brick.Material= tab[4]
end
local brickData = HttpService:JSONDecode(brickJSON)
createBrick(brickData) --this line actually spawns the brick
The function can also be wrapped in a pcall if you want to account for any possible datastore errors.
Encoding a whole model into a string
Say your player's 'building' is a model, you can use the above encode script to convert all parts inside a model into a json string to save.
local HttpService = game:GetService("HttpService")
local StuffWeWantToSave = {}
function getPartData(part)
return( {part.Size,part.Position,part.BrickColor,part.Material} )
end
local model = workspace.Building --change this to what the model is
local modelTable = model:Descendants()
for i,v in pairs(modelTable) do
if v:IsA("Part") or v:IsA("WedgePart") then
table.insert(StuffWeWantToSave, HttpService:JSONEncode(getPartData(modelTable[v])))
end
end
Decoding a string into a whole model
This will probably occur when the server is loading a player's data.
local HttpService = game:GetService("HttpService")
local SavedStuff = game:GetService("DataStoreService"):GetDataStore("blabla") --I don't know how you save your data, so you'll need to adjust this and the rest of the scripts (as long as you've saved the string somewhere in the player's DataStore)
function createBrick(tab)
local brick = Instance.new("Part")
brick.Parent = <insert parent here>
brick.Size = tab[1]
brick.Position= tab[2]
brick.BrickColor= tab[3]
brick.Material= tab[4]
end
local model = Instance.new("Model") --if you already have 'bases' for the players to load their stuff in, remove this instance.new
model.Parent = workspace
for i,v in pairs(SavedStuff) do
if v[1] ~= nil then
CreateBrick(v)
end
end
FilteringEnabled
If your game uses filteringenabled, make sure that only the server handles saving and loading data!! (you probably already knew that) If you want the player to save by clicking a gui button, make the gui button fire a RemoteFunction that sends their base's data to the server to convert it to a string.
BTW I'm not that good at scripting so I've probably made a mistake somehwere.. good luck though
Crabway's answer is correct in that the HttpService's JSONEncode and JSONDecode methods are the way to go about tackling this problem. As it says on the developer reference page for the DataStoreService, Data is ... saved as a string in data stores, regardless of its initial type. (https://developer.roblox.com/articles/Datastore-Errors.) This explains the error you received, as you cannot simply push a table to the data store; instead, you must first encode a table's data into a string using JSONEncode.
While I agree with much of Crabway's answer, I believe the function createBrick would not behave as intended. Consider the following trivial example:
httpService = game:GetService("HttpService")
t = {
hello = 1,
goodbye = 2
}
s = httpService:JSONEncode(t)
print(s)
> {"goodbye":2,"hello":1}
u = httpService:JSONDecode(s)
for k, v in pairs(u) do print(k, v) end
> hello 1
> goodbye 2
As you can see, the table returned by JSONDecode, like the original, uses strings as keys rather than numeric indices. Therefore, createBrick should be written something like this:
function createBrick(t)
local brick = Instance.new("Part")
brick.Size = t.Size
brick.Position = t.Position
brick.BrickColor = t.BrickColor
brick.Material = t.Material
-- FIXME: set any other necessary properties.
-- NOTE: try to set parent last for optimization reasons.
brick.Parent = t.Parent
return brick
end
As for encoding a model, calling GetChildren would produce a table of the model's children, which you could then loop through and encode the properties of everything within. Note that in Crabway's answer, he only accounts for Parts and WedgeParts. You should account for all parts using object:IsA("BasePart") and also check for unions with object:IsA("UnionOperation"). The following is a very basic example in which I do not store the encoded data; rather, I am just trying to show how to check the necessary cases.
function encodeModel(model)
local children = model:GetChildren()
for _, child in ipairs(children) do
if ((child:IsA("BasePart")) or (child:IsA("UnionOperation"))) then
-- FIXME: encode child
else if (child:IsA("Model")) then
-- FIXME: using recursion, loop through the sub-model's children.
end
end
return
end
For userdata, such as Vector3s or BrickColors, you will probably want to convert those to strings when you go to encode them with JSONEncode.
-- Example: part with "Brick red" BrickColor.
color = tostring(part.BrickColor)
print(string.format("%q", color))
> "Bright red"
I suggest what #Crabway said, use HttpService.
local httpService = game:GetService("HttpService")
print(httpService:JSONEncode({a = "b", b = "c"}) -- {"a":"b","b":"c"}
But if you have any UserData values such as Vector3s, CFrames, Color3s, BrickColors and Enum items, then use this library by Defaultio. It's actually pretty nice.
local library = require(workspace:WaitForChild("JSONWithUserdata"))
library:Encode({Vector3.new(0, 0, 0)})
If you want a little documentation, then look at the first comment in the script:
-- Defaultio
--[[
This module adds support for encoding userdata values to JSON strings.
It also supports lists which skip indices, such as {[1] = "a", [2] = "b", [4] = "c"}
Userdata support is implemented by replacing userdata types with a new table, with keys _T and _V:
_T = userdata type enum (index in the supportedUserdataTypes list)
_V = a value or table representing the value
Follow the examples bellow to add suppport for additional userdata types.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Usage example:
local myTable = {CFrame.new(), BrickColor.Random(), 4, "String", Enum.Material.CorrodedMetal}
local jsonModule = require(PATH_TO_MODULE)
local jsonString = jsonModule:Encode(myTable)
local decodedTable = jsonModule:Decode(jsonString)
--]]

How to get current position of iterator in ByteString?

I have an instance of ByteString. To read data from it I should use it's iterator() method.
I read some data and then I decide than I need to create a view (separate iterator of some chunk of data).
I can't use slice() of original iterator, because that would make it unusable, because docs says that:
After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old
iterator is undefined, subject to change, and may result in changes to
the new iterator as well.
So, it seems that I need to call slice() on ByteString. But slice() has from and until parameters and I don't know from. I need something like this:
ByteString originalByteString = ...; // <-- This is my input data
ByteIterator originalIterator = originalByteString .iterator();
...
read some data from originalIterator
...
int length = 100; // < -- Size of the view
int from = originalIterator.currentPosition(); // <-- I need this
int until = from + length;
ByteString viewOfOriginalByteString = originalByteString.slice(from, until);
ByteIterator iteratorForView = viewOfOriginalByteString.iterator(); // <-- This is my goal
Update:
Tried to do this with duplicate():
ByteIterator iteratorForView = originalIterator.duplicate()._2.take(length);
ByteIterator's from field is private, and none of the methods seems to simply return it. All I can suggest is to use originalIterator.duplicate to get a safe copy, or else to "cheat" by using reflection to read the from field, assuming reflection is available in your deployment environment.