The following is the code in typescript,
count: number;
this.count is accessed from html component.
console.log(this.count) gives me 5.
var arrObj:number[] = new Array(this.count)
console.log(arrObj.length);
Here the length of the array is always 1.
var arrObj:number[] = new Array(5)
console.log(arrObj.length);
Output: 5
var arrObj:number[] = new Array(this.count)
console.log(arrObj.length);
Output:1
Why is the global variable length is always 1?
An array can also be created using the Array object. The Array constructor can be passed.
A numeric value that represents the size of the array
or A list of comma separated values.
ref:https://www.tutorialspoint.com/typescript/typescript_arrays.htm
you are initializing the array again and again... from the code that you've shared, when you do:
var arrObj:number[] = new Array(5)
you're initializing the array of size 5 in this case, which will all be undefined
and when you do...
var arrObj:number[] = new Array(1)
you're initializing the array with a single item, which will be undefined in this case
you should do this once var arrObj:number[] = []
and then push the value in the array by doing arrObj.push(yourValue)
demo on stackblitz
'this' always works in scope and array constructor always accept static values it will never do eval(this.something), so when you pass 'this.count' it is passed as 1 undefined static value that is why it is becoming one length array(undefined being a static value in itself).
Also to be noted array constructor accepts only
A numeric value that represents the size of the array or
list of comma separated values.
In your case if you need alternate solution then initialize array empty and then assign arrObj.length = this.count
Related
I have a problem with converting a string variable to TObject.
I have a query that returns two columns to me. In the first column I have varchar values that I translate into strings, and in the second column I have int values.
I want to fill a ComboBox in this way with these values:
cbx1-> AddItem (DataSet1->DataSet->Fields->Field[0]->AsString, (TObject *) (int) DataSet1->DataSet->Fields->Field[1];
As I refer to the second value which is int type, I receive some bushes, e.g., xD, etc.
By trying to convert this value to string, eg:
String temp = IntToStr (DataSet1->DataSet->Fields->Field[1]);
cbx1-> AddItem (DataSet1->DataSet->Fields->Field[0]->AsString, (TObject *) temp;
I receive an error message:
cannot cast from 'AnsiString' to 'TObject'
I do not know what further I can do to convert this value.
You cannot cast an AnsiString value to a TObject* pointer. You can only cast an integer value, or a pointer value, to a TObject* pointer. AnsiString is neither of those.
You are not retrieving the int value from the 2nd field correctly anyway. Field[1] is a pointer to an actual TField object in the Fields collection. That pointer is what you are trying to store in your ComboBox, NOT the int value that the TField represents.
You need to call Fields[1]->AsInteger to get the int value of the 2nd field, similar to how you use Fields[0]->AsString to get the string value of the 1st field:
cbx1->AddItem(
DataSet1->DataSet->Fields->Field[0]->AsString,
(TObject*) DataSet1->DataSet->Fields->Field[1]->AsInteger
// in C++, using reinterpret_cast is preferred over C-style casting:
// reinterpret_cast<TObject*>(DataSet1->DataSet->Fields->Field[1]->AsInteger)
);
This is no different than the code in your previous question:
cbx1->AddItem("one",(TObject*)1);
You are now just placing the literals "one" and 1 with runtime variables of equivalent types.
I'm guessing this question is going to apply to many similar languages other than MQL4 such as c++ (which I also forget how to use) which require you manually specify when you are passing by reference.
Method reference:
int[] previous = GetPrevious(i, ZigZagBuffer);
Method definition:
int GetPrevious[](int current, const double& buffer[])
{
int count = 0;
int result[];
// calculate count
ArrayResize(result,count);
// fill array
return result;
}
The resulting compile error is:
"Invalid Array Access"
From what I understand, this is because array's can only be passed by reference, but you have to explicitly state that you are passing it by reference. But the more I look up the syntax for passing by reference, the more I find articles about passing parameter by reference. (which I already know how to do as you can see in the code example.)
What is the syntax to assign the output of a method to a variable?
In case it matters, I only need to read the array multiple times; I'm not needing to alter or re-assign it after it is declared.
You cannot return array. You have to create it and pass into the function, fill inside the function and that's it.
OnTick(){
double array[]; //declaration of the array
fillArray(array,10); //passing array by ref, updating it there
Print(array[0]=0 && array[9]=9);//returns true
}
void fillArray(double &array[],int size){
ArrayResize(array,size);
for(int i=0;i<size;i++){array[i]=i;}
}
I'm getting a response in JSON format, which contains an _id that is stored as an ObjectID in Mongodb on the server side. However, I change it into a String, and it still won't let me add it. Is it because it has numbers? I need the element to be identifiable by the id, so if I can't append this way, is there any other way I can reference the element by the id?
var group = d3.select("#containerthing");
var id = response._id.toString();
console.log(id);
//5802bc044f6313c1097de4a2
var responseNode = group.append(id).attr("fill","black").attr("x", 15).attr("y", 15).attr("width", 190).attr("height", 90);
//InvalidCharacterError: String contains an invalid character
I believe that I understand your problem.
D3's .append():
If the specified type is a string, appends a new element of this type (tag name) as the last child of each selected element, or the next following sibling in the update selection if this is an enter selection. [...] This function should return an element to be appended. (The function typically creates a new element, but it may instead return an existing element.
Why .append() work fine if you pass 'foo'? Because D3 append a custom tag element. If you see in your console I'am sure that you will see <foo>...</foo>
Why .append() work wrong if you pass '5802bc044f6313c1097de4a2'? A custom tag element can't start with a number. You don't use _id, you should try to find another pattern for identify your element.
I hope that helps
The reason was that you can't start elements with numbers. I had to do:
var responseNode = group.append("n"+id).attr("fill","black").attr("x", 15).attr("y", 15).attr("width", 190).attr("height", 90);
to get it to work.
I am trying to constrain my list items to be equal to certain values under certain conditions.
For that I have devised a define as computed macro that
define <num_prob_constraints'struct_member> "CHECK_and_SET_CONSTRAINTS <lst'exp>" as computed {
//var cur : list of uint = <lst'exp>.as_a(list of uint);
var t : uint = <lst'exp>.as_a(list of uint).size();
print t;
for i from 1 to 4 {
result = append(result,"keep ",<lst'exp>,"[",i,"]==",i,"=> ",<lst'exp>,"[",i,"]==389; \n");
};
};
and in my code I use this macro like this:
struct schedule{
n : uint;
sched_w : list of list of int;
CHECK_and_SET_CONSTRAINTS sched_w;
};
But this does not work. First, it prints some random size (From the macro) instead of the list’s real size.
Secondly, I get errors of this sort:
*** Error: '1' is of type 'int', while expecting type 'list of int'.
in code generated by macro defined at line 3 in
sports_sched_macro.e
keep sched_w[1]==1=> sched_w[1]==389;
expanded at line 8 in sports_sched.e
CHECK_and_SET_CONSTRAINTS sched_w;
Any ideas on what is wrong here?
Macros are simply code substituts. Their function is simply to replace some string with another (calculated or not) during the parsing phase.
This means that the macro will be deployed where you used it in the parsing phase which precedes the generation phase. So, in fact, the list does not exist yet, and you cannot access it’s size and items.
More specifically, your macro is deployed this way:
struct schedule {
n : uint;
sched_w : list of list of int;
keep sched_w[1]==2=> sched_w[1]==389;
keep sched_w[2]==2=> sched_w[2]==389;
...
...
};
The error message you received tell you that you cannot access specific list items explicitly (since the list size and item’s values are yet undetermined).
If you want to keep your list with size 4, and if the value is 2 you want to replace it with 389, you may need to use the post_generate() method, as you are trying to access values that are already assigned to the list items:
keep sched_w.size()==4;
post_generate() is also{
for each in sched_w {
if (it==2) {it=389};
};
};
Are you sure you want to constrain a 2-dimensional list? This looks a bit different. E.g. for an array schedule[4][1]:
schedule: list of list of int;
keep schedule.size() == 4;
keep for each (sublist) in schedule {
sublist.size() == 1;
for each (elem) in sublist {
...
};
};
In my mirth implementation (Mirth Connect Server 2.2.1) I have a GlobalMap that contains keys and properties comes from external property file. How do I get the key set from the Globalmap and iterate it to get the values?
You can iterate through the global map like so:
for each (key in globalMap.getVariables().keySet().toArray())
logger.info(key+': '+$g('key'));
I'm not sure exactly how you're initializing your key/value set, but here's a basic rundown of what I do.
To stick a key/value set in the GlobalMap:
//I will assume that you have your own routine for initializing the
//kv set from your property file
var kvPairs = {'key1':'value1',
'key2':'value2',
'key3':'value3'};
globalMap.put('keyValuePairs',kvPairs);
To extract the set from the GlobalMap:
// Method 1
// Grab directly from GlobalMap object.
var kvPairs = globalMap.get('keyValuePairs');
// Method 2
// Use the Mirth shorthand to search all map objects until the
// desired variable is located.
var kvPairs = $('keyValuePairs');
To iterate through the set:
// Method 1
// If you need to access both the keys and the associated values, then
// use a for in loop
for (var key in kvPairs)
{
var value = kvPairs[key];
// you now have key and value, and can use them as you see fit
}
// Method 2
// If you only need the values, and don't need the keys, then you can use
// the more familiar for each in loop
for each (var value in kvPairs)
{
// you now have value, and can use it as you see fit;
}