I am trying to iterate over rapidjson kArrayTye, which is an array of objects and change the value of locale object.
The array looks like
[{"key":"dsn","value":"TestDSN"},{"key":"deviceType","value":"TestDeviceType"},{"key":"productID","value":"TestProduct"},{"key":"locale","value":"de-DE"},{"key":"PAGETYPE","value":"SETTINGS"}]
I want to change the locale value "de-DE" to another string. Please help. I have tried below code which is not working.
for (rapidjson::Value::ConstValueIterator itr = document.Begin(); itr != document.End(); ++itr) {
if (itr->HasMember("key")) {
std::string str = (*itr)["key"].GetString();
if((str).compare("locale") == 0) {
rapidjson::Value localePayload(rapidjson::kObjectType);
rapidjson::Value value("Testnew");
(*itr)["value"] = value;
}
}
}
Related
i need a hint cause i don‘t know how to start.
I want to display a string char after char with a short delay but I’m not sure how to do it.
Should i convert the string into an array and display this array in a ForEach or is it possible to do this with string manipulation?
Thanks for every hint :-)
Michael
Here's an example where you can input a String. It will turn it into an array of Strings (for each character), add them onto the screen using an HStack and Text objects. Each Text has initial .opacity of 0.0 and then a function is called that will loop through each Text, turning the .opacity to 1.0.
struct CharView: View {
var characterArray: [String]
#State var characterLoopIndex: Int = -1
let loopDuration: Double = 0.5
init(input: String) {
characterArray = input.map { String($0) }
}
var body: some View {
HStack(spacing: 0) {
ForEach(characterArray.indices) { index in
Text("\(characterArray[index])")
.opacity(characterLoopIndex >= index ? 1 : 0)
.animation(.linear(duration: loopDuration))
}
}
.onAppear(perform: {
startCharacterAnimation()
})
}
func startCharacterAnimation() {
let timer = Timer.scheduledTimer(withTimeInterval: loopDuration, repeats: true) { (timer) in
characterLoopIndex += 1
if characterLoopIndex >= characterArray.count {
timer.invalidate()
}
}
timer.fire()
}
}
Usage:
CharView(input: "This is a test string")
In python, I often use strings as templates, e.g.
templateUrl = '{host}/api/v3/{container}/{resourceid}'
params = {'host': 'www.api.com', 'container': 'books', 'resourceid': 10}
api.get(templateUrl.format(**params))
This allows for easy base class setup and the like. How can I do the same in dart?
I'm assuming I will need to create a utility function to parse the template and substitute manually but really hoping there is something ready to use.
Perhaps a TemplateString class with a format method that takes a Map of name/value pairs to substitute into the string.
Note: the objective is to have a generic "format" or "interpolation" function that doesn't need to know in advance what tags or names will exist in the template.
Further clarification: the templates themselves are not resolved when they are set up. Specifically, the template is defined in one place in the code and then used in many other places.
Dart does not have a generic template string functionality that would allow you to insert values into your template at runtime.
Dart only allows you to interpolate strings with variables using the $ syntax in strings, e.g. var string = '$domain/api/v3/${actions.get}'. You would need to have all the variables defined in your code beforehand.
However, you can easily create your own implementation.
Implementation
You pretty much explained how to do it in your question yourself: you pass a map and use it to have generic access to the parameters using the [] operator.
To convert the template string into something that is easy to access, I would simply create another List containing fixed components, like /api/v3/ and another Map that holds generic components with their name and their position in the template string.
class TemplateString {
final List<String> fixedComponents;
final Map<int, String> genericComponents;
int totalComponents;
TemplateString(String template)
: fixedComponents = <String>[],
genericComponents = <int, String>{},
totalComponents = 0 {
final List<String> components = template.split('{');
for (String component in components) {
if (component == '') continue; // If the template starts with "{", skip the first element.
final split = component.split('}');
if (split.length != 1) {
// The condition allows for template strings without parameters.
genericComponents[totalComponents] = split.first;
totalComponents++;
}
if (split.last != '') {
fixedComponents.add(split.last);
totalComponents++;
}
}
}
String format(Map<String, dynamic> params) {
String result = '';
int fixedComponent = 0;
for (int i = 0; i < totalComponents; i++) {
if (genericComponents.containsKey(i)) {
result += '${params[genericComponents[i]]}';
continue;
}
result += fixedComponents[fixedComponent++];
}
return result;
}
}
Here would be an example usage, I hope that the result is what you expected:
main() {
final templateUrl = TemplateString('{host}/api/v3/{container}/{resourceid}');
final params = <String, dynamic>{'host': 'www.api.com', 'container': 'books', 'resourceid': 10};
print(templateUrl.format(params)); // www.api.com/api/v3/books/10
}
Here it is as a Gist.
Here is my solution:
extension StringFormating on String {
String format(List<String> values) {
int index = 0;
return replaceAllMapped(new RegExp(r'{.*?}'), (_) {
final value = values[index];
index++;
return value;
});
}
String formatWithMap(Map<String, String> mappedValues) {
return replaceAllMapped(new RegExp(r'{(.*?)}'), (match) {
final mapped = mappedValues[match[1]];
if (mapped == null)
throw ArgumentError(
'$mappedValues does not contain the key "${match[1]}"');
return mapped;
});
}
}
This gives you a very similar functionality to what python offers:
"Test {} with {}!".format(["it", "foo"]);
"Test {a} with {b}!".formatWithMap({"a": "it", "b": "foo"})
both return "Test it with foo!"
It's even more easy in Dart. Sample code below :
String host = "www.api.com"
String container = "books"
int resourceId = 10
String templateUrl = "$host/api/v3/$container/${resourceId.toString()}"
With the map, you can do as follows :
Map<String, String> params = {'host': 'www.api.com', 'container': 'books', 'resourceid': 10}
String templateUrl = "${params['host']}/api/v3/${params['container']}/${params['resourceId']}"
Note : The above code defines Map as <String, String>. You might want <String, Dynamic> (and use .toString())
Wouldn't it be simplest to just make it a function with named arguments? You could add some input validation if you wanted to.
String templateUrl({String host = "", String container = "", int resourceid = 0 }) {
return "$host/api/v3/$container/$resourceId";
}
void main() {
api.get(templateUrl(host:"www.api.com", container:"books", resourceid:10));
}
I want to know weather is is possible or not, a way to call different classes on the basis of an integer value without conditional statements like switch case?
What I am having is:
int val = // getting some value here from a method
String data = // getting some value here from a method
switch(val)
{
case 1:
{
new TempClass1(data);
break;
}
case 2:
{
new TempClass2(data);
break;
}
}
What I want is like:
int val = // getting some value here from a method
String data = // getting some value here from a method
new TempClass(val, data);
This should call the object of TempClass1 or TempClass1 as per "val"
Any help will be appreciated.
Maybe use a Factory for the classes, assuming your two classes share a base class named TempBaseClass:
class TempClassFactory {
static public TempBaseClass getTempClass(int val, String data)
{
switch(val)
{
case 1:
{
return new TempClass1(data);
break;
}
case 2:
{
return new TempClass2(data);
break;
}
default:
throw new Exception("Bad value");
}
}
}
int val = // getting some value here from a method
String data = // getting some value here from a method
TempClassFactory::getTempClass(val, data);
I am trying to understand how this convertingStringToInt method works. I am reading a file, storing the values in an array and am to pass those values to the method to be converted. In the parameters of convertingStringToInt, I have (String number) I don't get where the String "number" is getting its values. So I am passing in a string called numbers, but how is that newly created String associated with any of the values in my file...?!?
I am trying to understand the cause all the return numbers are the error code -460 except the last digit in the file. So the String numbers is associated with the file somehow I just don't get how...
public static void read_file()
{
try {
File file = new File("randomNumbers.txt");
Scanner scan = new Scanner(file);
int amountOfNumbersInFile = convertingStringToInt(scan.nextLine()); // read the first line which is 100 to set array size
global_numbers = new int[amountOfNumbersInFile]; // set the array size equal to the first line read which is 100
for (int index = 0; index < amountOfNumbersInFile; index++)
{
String line = scan.nextLine();
global_numbers [index] = convertingStringToInt(line);
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
public static int convertingStringToInt(String numbers) //what does string "number" equal? why/where is it declared?
{
String numbers = scan.nextInt();
try {
return Integer.parseInt(numbers);
} catch (NumberFormatException n) {
return -460;
}
}
I have global_numbers declared as a global variable.
so the first thing u need understand is what u have in your txt file
if in this file you have only number is ok use stringToInt
but if you have words this never work properly
I have the following code which copies property values from one object to another objects by matching their property names:
public static void CopyProperties(object source, object target,bool caseSenstive=true)
{
PropertyInfo[] targetProperties = target.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
PropertyInfo[] sourceProperties = source.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (PropertyInfo tp in targetProperties)
{
var sourceProperty = sourceProperties.FirstOrDefault(p => p.Name == tp.Name);
if (sourceProperty == null && !caseSenstive)
{
sourceProperty = sourceProperties.FirstOrDefault(p => p.Name.ToUpper() == tp.Name.ToUpper());
}
// If source doesn't have this property, go for next one.
if(sourceProperty ==null)
{
continue;
}
// If target property is not writable then we can not set it;
// If source property is not readable then cannot check it's value
if (!tp.CanWrite || !sourceProperty.CanRead)
{
continue;
}
MethodInfo mget = sourceProperty.GetGetMethod(false);
MethodInfo mset = tp.GetSetMethod(false);
// Get and set methods have to be public
if (mget == null)
{
continue;
}
if (mset == null)
{
continue;
}
var sourcevalue = sourceProperty.GetValue(source, null);
tp.SetValue(target, sourcevalue, null);
}
}
This is working well when the type of properties on target and source are the same. But when there is a need for casting, the code doesn't work.
For example, I have the following object:
class MyDateTime
{
public static implicit operator DateTime?(MyDateTime myDateTime)
{
return myDateTime.DateTime;
}
public static implicit operator DateTime(MyDateTime myDateTime)
{
if (myDateTime.DateTime.HasValue)
{
return myDateTime.DateTime.Value;
}
else
{
return System.DateTime.MinValue;
}
}
public static implicit operator MyDateTime(DateTime? dateTime)
{
return FromDateTime(dateTime);
}
public static implicit operator MyDateTime(DateTime dateTime)
{
return FromDateTime(dateTime);
}
}
If I do the following, the implicit cast is called and everything works well:
MyDateTime x= DateTime.Now;
But when I have a two objects that one of them has a DateTime and the other has MyDateTime, and I am using the above code to copy properties from one object to other, it doesn't and generate an error saying that DateTime can not converted to MyTimeDate.
How can I fix this problem?
One ghastly approach which should work is to mix dynamic and reflection:
private static T ConvertValue<T>(dynamic value)
{
return value; // This will perform conversion automatically
}
Then:
var sourceValue = sourceProperty.GetValue(source, null);
if (sourceProperty.PropertyType != tp.PropertyType)
{
var method = typeof(PropertyCopier).GetMethod("ConvertValue",
BindingFlags.Static | BindingFlags.NonPublic);
method = method.MakeGenericMethod(new[] { tp.PropertyType };
sourceValue = method.Invoke(null, new[] { sourceValue });
}
tp.SetValue(target, sourceValue, null);
We need to use reflection to invoke the generic method with the right type argument, but dynamic typing will use the right conversion operator for you.
Oh, and one final request: please don't include my name anywhere near this code, whether it's in comments, commit logs. Aargh.