I have an multi-dimensional associated array maplist that is such like below,
Now, I would like to convert it as an object such image is below,
The object should be arrange as such a way that array id will be object key and array name will be object value according to the maplist object image.
If I reduce array to a single object that is something like below,
let keyedOb = maplist.reduce((o,v) =>{ o[v.id] = v.name; return o},{})
Then, It will be shown as below image,
to reduce your array to a single object you can do something like
let keyedOb = maplist.reduce((o,v) =>{ o[v.id] = v.name; return o},{})
Related
I have been trying to filter an Array by its props and not by its value so my original array would be -
const orignalArray =[
{id: 1, name:"jim", email:"jim#mail.com",age:20},
{id: 1, name:"jom", email:"jom#mail.com",age:30}
]
id like to be able to use (n) amount of filters.
My output array would look ideally look like this
const filterList["id","age"]
const newArray=[{name:"jim", email:"jim#mail.com"},{ name:"jom", email:"jom#mail.com"}]
I have tried to use filter() but cant seem to get it to work.
any help is much appreciated.
In this case you aren't filtering the array rather creating a new one based on the original with derived elements from each. To achieve this you can use the array map function to loop over the array and create a new one with new objects without the desired properties, e.g.:
function removeArrayElementProps(arr, propsToRemove) {
return arr.map((element) => {
// Create a copy of the original element to avoid modifying the original
const newElement = {...element};
// Remove the desired properties from the new element
propsToRemove.forEach((propToRemove) => {
delete newElement[propToRemove];
});
// Returning the modified element in map puts it in thew new arry
return newElement;
});
}
Then you simply call:
const newArr = removeArrayElementProps(orignalArray, ['id','age']);
This loops over the array, creates a copy of each element, and removes the specified properties from the element.
I am pushing an object into an array but cannot do it?
I'm doing it like this
this.passData = this.tribeForm.value;
var id = {"tribe_id": 1}
this.passData.push(id)
This is the value in the tribeForm
I also tried
var id = {tribe_id: 1}
and
this.passData.splice(0,0, id)
and
this.passData = Array.prototype.slice(id)
and
this.passData.concat(id)
but it all ends up with
TypeError: this.passData.push/splice/concat is not a function
The question is not that clear, But I understood you are manipulating form data, value of form data returns an Object, Not an array. Objects in JavaScript are represented as key-value pairs, (or attribute-value) pairs.
Example :
var object = {
name : "Jhon",
grade : 12,
gpa : 8.12
}
It is just a collection of key-value pairs, push(), concat() and other methods are supported only for Arrays not for Objects. You can achieve whatever you want simply by creating a new key/attribute and assigning the value to it.
this.passData = this.tribeForm.value
this.passData['tribe_id'] = 1
//or, Objects can also contain nested object
this.passData['someKey'] = {'tribe_id' : 1}
You can create an empty array and push objects to it
Example :
var exampleArray = []
exampleArray.push({'tribe_id' : 1})
Now, it works because exampleArray is an Array not JS object.
Thanks for A2A
First, you need to understand the error:
TypeError: this.passData.push/splice/concat is not a function
Push/splice/concat is functions for Array and because of that the console is yelling at you that the passData is not an Array.
Make sure your passData is an Array and you will able to do so.
I'm manipulating an array of objects that i get from an http request containing coordinates to create markers in google-maps , but i need to eliminate all the null values in the array. I'm trying with compact but it gives back the same array unchanged.
//this is the resulting array structure
var array=
[{"id":0,"latitude":45.17850875854492,"longitude":7.773523330688477},{"id":1,"latitude":45.122344970703125,"longitude":7.7135162353515625},{"id":2,"latitude":null,"longitude":null},{"id":3,"latitude":45.11630630493164,"longitude":7.730717658996582},{"id":4,"latitude":45.116214752197266,"longitude":7.730687141418457},{"id":5,"latitude":null,"longitude":null}]
var comp =_.compact(array)
i dont get any error in the cosole , but the variable comp return the same exact array without removing null values
All your values are arrays, and the null is a value of your properties. The _.compact() method works with primitives.
Use _.reject() and check with _.isNull if the properties are null, and the object should be removed:
const array =
[{"id":0,"latitude":45.17850875854492,"longitude":7.773523330688477},{"id":1,"latitude":45.122344970703125,"longitude":7.7135162353515625},{"id":2,"latitude":null,"longitude":null},{"id":3,"latitude":45.11630630493164,"longitude":7.730717658996582},{"id":4,"latitude":45.116214752197266,"longitude":7.730687141418457},{"id":5,"latitude":null,"longitude":null}]
const result = _.reject(array, ({ latitude, longitude }) =>
_.isNull(latitude) || _.isNull(longitude)
)
console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
You can use _.pickBy()
Creates an object composed of the object properties predicate returns truthy for
lodash
This applies on object so for an array you can use that:
var comp = _.map(array, item => _.pickBy(item));
I have a dictionary containing UIColor objects hashed by an enum value, ColorScheme:
var colorsForColorScheme: [ColorScheme : UIColor] = ...
I would like to be able to extract an array of all the colors (the values) contained by this dictionary. I thought I could use the values property, as is used when iterating over dictionary values (for value in dictionary.values {...}), but this returns an error:
let colors: [UIColor] = colorsForColorSchemes.values
~~~~~~~~~~~~~~~~~~~~~^~~~~~~
'LazyBidrectionalCollection<MapCollectionView<Dictionary<ColorScheme, UIColor>, UIColor>>' is not convertible to 'UIColor'
It seems that rather than returning an Array of values, the values method returns a more abstract collection type. Is there a way to get an Array containing the dictionary's values without extracting them in a for-in loop?
As of Swift 2.0, Dictionary’s values property now returns a LazyMapCollection instead of a LazyBidirectionalCollection. The Array type knows how to initialise itself using this abstract collection type:
let colors = Array(colorsForColorSchemes.values)
Swift's type inference already knows that these values are UIColor objects, so no type casting is required, which is nice!
You can map dictionary to an array of values:
let colors = colorsForColorScheme.map { $0.1 }
Closure takes a key-value tuple from dictionary and returns just a value. So, map function produces an array of values.
More readable version of the same code:
let colors = colorsForColorScheme.map { (scheme, color) in
return color
}
UPDATE
From Xcode 9.0, dictionary values can be accessed using values property, which conforms to Collection protocol:
let colors = colorsForColorScheme.values
Typically you just want it as an array:
let colors = Array(dict.values)
and that's it.
Use colorsForColorScheme.map({$0.value})
you can create an extension on LazyMapCollection
public extension LazyMapCollection {
func toArray() -> [Element]{
return Array(self)
}
}
colorsForColorSchemes.values.toArray() or colorsForColorSchemes.keys.toArray()
Firstly, from the following statement, it seems that your variable(dictionary) name is colorsForColorScheme
var colorsForColorScheme: [ColorScheme : UIColor] = ...
while you are trying to get the values from colorsForColorSchemes dictionary when you did-
let colors: [UIColor] = colorsForColorSchemes.values
which should give you a compile time error. Anyways I am assuming that you had a typo, and you dictionary's name is colorsForColorSchemes. So, here is the solution-
As mentioned earlier, because of the type inference property in swift, your code can infer that the returned type from the .values function is returning an array of UIColor. However, Swift wants to be type-safe, so when you store the values in the colors array, you need to explicitly define that. For swift 5 and above, now you could just do following-
let colors = [UIColor](colorsForColorSchemes.values)
You can also use flatMap:
let colors = colorsForColorScheme.values.flatMap { $0 }
I've found this to be the most useful in Swift 5:
colorsForColorSchemes.allValues
See docs - https://developer.apple.com/documentation/foundation/nsdictionary/1408915-allvalues
In the library of the .fla file I have a square exported as Class "cuad" on frame 1
I want to create an Array with 100 squares so as to move them later
So I do like this:
for (var i:uint = 0; i<100;i++)
{
var cuad_mc = new cuad();
addChild(cuad_mc);
myArray.push("cuad_mc");
trace(myArray[i]);
}
I have a runtime error
The error you experience is
Error #1069: Did not find alpha propiety in the String and there is not any value predetermined
The problem comes from your line
myArray.push("cuad_mc");
What you are doing here is pushing a String Object into your Array, not the cuad Object you want. String Objects don't have Alpha values, or x values.
What you want to do is
myArray.push(cuad_mc);
cuad_mc (without the " quotation marks) is a reference to the object you just created.
This should solve your problem. I also recommend using Vectors instead of Array if you only need to store one type of Object. Like this:
var myArray:Vector<cuad> = new Vector<cuad>();
for(var i:int=0;i<100;i++){
var cuad_mc:cuad = new cuad();
addChild(cuad_mc);
myArray.push(cuad_mc);
trace(myArray[i]);
}
Vectors are just like Arrays, but they only allow one specific type, so that a situation like yours doesn't occur.