List listFinal = [];
So listFinal have values from multiple list inside like below.
[["test: 111-333-5555", "test2: 222-333-4555"], ["test3: 555-333-2222"]]
How do I make this list so that it only extract numbers and separate with comma?
End result should be like
[1113335555, 2223334555, 5553332222]
I can think of trimming or regexp but not sure how to pull this off.
many thanks.
Try this
void main() {
List<String> numberList=[];
List<List<dynamic>> demoList=[["test: 111-333-5555", "test2: 222-333-4555"], ["test3: 555-333-2222"]];
for(int i=0;i<demoList.length;i++){
numberList.addAll(demoList[i].map((e) => e.toString().split(":")[1].replaceAll("-", "")).toList());
}
print(numberList.toString());
}
Here is an example to get you started. This doesn't handle things like malformed input strings. First step is to "flatten" the list with .expand, and then for each element of the flattened iterable use a regex to extract the substring. Other options might include using .substring to extract exactly the last 12 characters of the String.
You can see this in action on dartpad.
void main() {
final input = [
['test: 111-333-5555', 'test2: 222-333-4555'],
['test3: 555-333-2222']
];
final flattened = input.expand((e) => e); // un-nest the lists
// call extractNumber on each element of the flattened iterable,
// then collect to a list
final result = flattened.map(extractNumber).toList();
print(result);
}
final _numberRegExp = RegExp(r'.*: ([\d-]+)$');
int extractNumber(String description) {
var numberString = _numberRegExp.firstMatch(description).group(1);
return int.parse(numberString.replaceAll('-', ''));
}
Let's do this in a simple way.
List<List<String>> inputList = [
["test: 111-333-5555", "test2: 222-333-4555"],
["test3: 555-333-2222"]
];
List resultList = [];
print('Input List : $inputList');
inputList.forEach((subList){
subList.forEach((element){
var temp = element.split(' ')[1].replaceAll('-', '');
resultList.add(temp);
});
});
print('Output List : $resultList');
Here I have taken your list as inputList and stored the result in resultList.
For each element of inputList we get a sub-list. I have converted the elements of that sub-list into the needed format and added those into a List.
Happy Coding :)
Related
Lets Say this is My Text. Now I want to Extract All 4 Variable Separately from the text
"ScanCode=? scanMsg= ? ItemName=? ID= ?\n"
Please Help i need this is Dart, Flutter
The solution I developed first splits the data according to the space character. It then uses the GetValue() method to sequentially read the data from each piece. The next step will be to use the data by transforming it accordingly.
This example prints the following output to the console:
[ScanCode=1234, ScanMessage=Test, Itemname=First, ID=1]
[1234, Test, First, 1]
The solution I developed is available below:
void main()
{
String text = "ScanCode=1234 ScanMessage=Test ItemName=First ID=1";
List<String> original = text.split(' ');
List<String> result = [];
GetValue(original, result);
print(original);
print(result);
}
void GetValue(List<String> original, List<String> result)
{
for(int i = 0 ; i < original.length ; ++i)
{
result.insert(i, original[i].split('=')[1]);
}
}
I have a function which creates a sublist from a large(very large list). After creating this list, the function goes on treating it (deleting duplicates, sorting...).
As long as the list was not too big, it worked fine. But now, I get "The Getter length was called on null". I suppose, it's because the second part of the function (after the loop) starts before the sublist is completed... so it doesn't work...
How can we force the function to wait for the loop to be over to continue the rest of the treatment ?
Is it with Async /Await ? Or can we do something like "While... something is not over...", or "As soon as something is done... do that" ? (My suggestions might be naive, but I am a beginner...)
Here is the code :
List themeBankFr() {
List<Map> themeBankFr = [];
for (Word word in wordBank) {
for (Thematique wordTheme in word.theme) {
themeBankFr.add({
'themeFr': wordTheme.themeFr,
'image': wordTheme.image,
});
}
}
// convert each item to a string by using JSON encoding
final jsonList = themeBankFr.map((item) => jsonEncode(item)).toList();
// using toSet - toList strategy
final uniqueJsonList = jsonList.toSet().toList();
// convert each item back to the original form using JSON decoding
final result = uniqueJsonList.map((item) => jsonDecode(item)).toList();
// sort the list of map in alphabetical order
result.sort((m1, m2) {
var r = m1['themeFr'].compareTo(m2['themeFr']);
if (r != 0) return r;
return m1['image'].compareTo(m2['image']);
});
return result;
}
i think i have a good answer that may helps you and it will as following
first create another function to do the work of for loops and this function returns a future of list that you need like below
Future<List<Map>> futureList(List wordBank){
List<Map> themeBankFr = [];
for (Word word in wordBank) {
for (Thematique wordTheme in word.theme) {
themeBankFr.add({
'themeFr': wordTheme.themeFr,
'image': wordTheme.image,
});
}
}
return Future.value(themeBankFr);
}
after that you can use this function inside your code and use it as async await and now you will never run the below lines before you return this array like below
List themeBankFr() async {
List<Map> themeBankFr = await futureList(wordBank);
// convert each item to a string by using JSON encoding
final jsonList = themeBankFr.map((item) => jsonEncode(item)).toList();
// using toSet - toList strategy
final uniqueJsonList = jsonList.toSet().toList();
// convert each item back to the original form using JSON decoding
final result = uniqueJsonList.map((item) => jsonDecode(item)).toList();
// sort the list of map in alphabetical order
result.sort((m1, m2) {
var r = m1['themeFr'].compareTo(m2['themeFr']);
if (r != 0) return r;
return m1['image'].compareTo(m2['image']);
});
return result;
}
i think this will solve your problem and i hope this useful for you
I have number of Strings coming from an API.
What I want is to merge all Strings together...
What I've done so far is store all Strings in an Array and convert that to a String:
var a = List<String>();
a.add("\n \u2022 " + "test1");
a.add("\n \u2022 " + "test2");
Result:
[•test1
•test2
]
Expected:
bulleted lists without [] .
Is there a better way to do this?
This code sample should answer your questions:
void main() {
const itemPrefix = " \u2022 ";
// create a growable list of strings
final strings = <String>[];
// add some items to it
strings.add("test1");
strings.add("test2");
// create a single string joining the items
String result = strings
// prepend the bullet point to each item
.map((item) => "${itemPrefix}$item")
// put a new-line between each item, joining the items to a String
.join('\n');
print(result);
}
I want to enter a array like [1,2,3,4,5] in the form field and use that form value as a parameter to bubblesort function to sort the array.How to implement this in flutter?
Keep it simple and just use the builtin json parser.
Like this:
List<int> nbs = List<int>.from(json.decode('[1,2,3,4]'));
Our string:
final hi = "[1,2,3,4,5]";
The regular expression used to remove the square brackets:
final regex = RegExp(r'([\[\]])');
Our string without any brackets after replacing them with nothing:
final justNumbers = hi.replaceAll(regex, ''); // 1,2,3,4,5
Our list of strings by splitting them by commas:
List<String> strings = justNumbers.split(',');
Now we parse our strings into integers (tryParse is used so that it returns null instead of throwing an exception):
List<int> numbers = strings.map((e) => int.tryParse(e)).toList();
Final
void main() {
final hi = "[1,2,3,4,5]";
final regex = RegExp(r'([\[\]])');
final justNumbers = hi.replaceAll(regex, '');
List<String> strings = justNumbers.split(',');
List<int> numbers = strings.map((e) => int.tryParse(e)).toList();
print(numbers);
}
Is there any way to find unique values between two lists without using a loop?
List<String> first = ['A','B','C','D'];
List<String> second = ['B','D'];
I need the result to be like this:
result = ['A','C'];
You can use where() with contains() methods from List:
void main() {
List<String> first = ['A','B','C','D'];
List<String> second = ['B','D'];
List<String> result = first.where((item) => !second.contains(item)).toList();
print(result); // [A, C]
}
Edit in DartPad.