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]);
}
}
Related
Looking for the same solution that was given in swift here - How to remove first word from a sentence in swift.
Anyone can help?
void main() {
String words = "hello world everyone";
List<String> word_l = words.split(" ");
String word = word_l.sublist(1,word_l.length).join(" ");
print(word);
}
Use as above code to remove first word from words. This work for multiple words more than 2.
You could just do this:
void main() {
var data = 'CITY Singapore';
data = data[0];
print(data);
}
I am trying to read data from a firebase real time database and store it in a list to use in my flutter app.
As seen in the code below, I start by creating a reference to the database. I also create some global variables, where "itemName" stores the name of the item in the database, "itemID" stores the id of each item in the database and "itemNames" is a list of all the item names in the database.
The "activate listeners" method listens to the database, and returns any values if they are changed. Each item ID starts with a J, and continues onto J1, J2, J3 etc. Hence I am using a for loop to access all the item IDs.
The issue I am having is that the itemNames are successfully being stored in the itemNames list, and can be see when I print the list within the for loop (The first print line).
However, when I try print the list value OUTSIDE the for loop, it prints an empty list for loop (second print line).
So in other words, the list is not retaining the elements added to it during the for loop.
Any help would be much appreciated!
final DatabaseReference _dbRef = FirebaseDatabase.instance.ref();
late StreamSubscription _dailySpecialStream;
//Stores the description of each menu item in the DB
String itemName = "";
String itemID = "";
List<String> itemNames = [];
//"Listens for any changes being made to the DB, and updates our app in real time"
void _activateListeners() {
for (int i = 0; i <= 10; i++) {
itemID = "J$i";
_dailySpecialStream =
_dbRef.child("menuItem/$itemID/itemName").onValue.listen((event) {
itemName = event.snapshot.value.toString();
itemNames.addAll([itemName]);
print(itemNames);
});
}
print(itemNames);
}
That is the expected behavior. Data is loaded from Firebase (and most modern cloud APIs) asynchronously, and while that is happening your main code continues to run.
You can most easily see this by placing some print statements:
print('before starting to load data');
for (int i = 0; i <= 10; i++) {
itemID = "J$i";
_dailySpecialStream =
_dbRef.child("menuItem/$itemID/itemName").onValue.listen((event) {
print('loaded data: %i');
});
}
print('after starting to load data');
If you run this, you'll see something like:
before starting to load data
after starting to load data
loaded data: 0
loaded data: 1
loaded data: 2
loaded data: 3
...
So as you can see the after print statement that is lowest in your code, actually printed before any of the data was loaded. This is probably not what you expected, but explains perfectly why the print statement you had outside the loop doesn't print the data: it hasn't been loaded yet!
The solution for this type of problem is always the same: you have to make sure the code that requires the data is inside the callback, or it is called from there, or it is otherwise synchronized.
A simple way to do the latter is by using get() instead of onValue, and then use await on the Future that is returns:
print('before starting to load data');
for (int i = 0; i <= 10; i++) {
itemID = "J$i";
_dailySpecial = await _dbRef.child("menuItem/$itemID/itemName").get();
print('loaded data %i: ${_dailySpecial.value}');
}
print('after starting to load data');
Now with this, the print statements will be in the order you expected.
I have this code which should stack multiple rows one on top of another in Flutter with the CSV library.
exportCsv(List<Drink> drinksFeed, List<Alcohol> alcoholFeed
) async {
List<List<dynamic>> rows = List<List<dynamic>>();
for (int i = 0; i < drinksFeed.length; i++) {
List<dynamic> row = List();
row.add(drinksFeed[i].id);
row.add(drinksFeed[i].name);
row.add(drinksFeed[i].description);
row.add(drinksFeed[i].price);
rows.add(row);
setState(() {
drinksFeed = drinkFeedback;
});
}
List<List<dynamic>> alcoholRows = List<List<dynamic>>();
for (int i = 0; i < alcoholFeed.length; i++) {
List<dynamic> row = List();
row.add(alcoholFeed[i].id);
row.add(alcoholFeed[i].name);
row.add(alcoholFeed[i].description);
row.add(alcoholFeed[i].price);
alcoholRows.add(row);
setState(() {
alcoholFeed = alcoholFeedback;
});
}
String drinkCsv = const ListToCsvConverter().convert(rows);
String alcoholCsv = const ListToCsvConverter().convert(alcoholRows);
f.writeAsString(drinkCsv);
f.writeAsString(alcoholCsv);
}
}
As you can see, it takes each element from a list and writes it as a string, but for some reason, it isn't stacking rows on top of one another (drinkCsv and alcoholCsv), it just shows the drinksCsv elements in the CSV file. This isn't the full code, because it's too long and I don't think it's relevant to show CSV export, but this should be enough.
So my question is, is it possible to stack multiple elements one on top of another in 1 csv file (drinkCsv + alcoholCsv in this case).
Maybe awaiting before writing again could solve the problem, also changing the mode to append so it continues writing at the end of the file
await f.writeAsString(drinkCsv);
await f.writeAsString(alcoholCsv, mode: FileMode.append);
the best solution I can come up is combining the 2 lists before doing the convert (I haven't used that ListToCsvConverter().convert() so I'm not sure how does the string result looks like)
String fileCsv = const ListToCsvConverter().convert([...rows, ...alcoholRows]);
await f.writeAsString(fileCsv);
That way maybe the converter do the correct append between the rows when converting to string
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 :)
i have created web application and using textbox and it can contains multiple line of data becoz i have set its textmode property is multiline.
my problem is that i want to check each line contain data or not so i using count variable which count how many line contain data.
string[] data;
int cntindex;
data = txt_invoicenumber.Text.ToString().Split("\n".ToCharArray());
cntindex = data.Length;
for (j = 0; j < cntindex; j++)
{
if (data[j]!="")
{
inv_count++;
}
}
Its not working.
Please help me.
I guess this is because new line is \r\n so there is a '\r' also on empty lines.
Change the if statement to:
if (data[j].Trim().Length != 0)
Firstly, You don't need to ToString() the .Text property as it is already a string.
try this
string[] lines = txt_invoicenumber.Text.Split(Environment.NewLine);
int lineCount = 0;
foreach(string line in lines)
{
if(!string.IsNullOrEmpty(line))
{
lineCount ++;
this.ProcessLine(line);
}
}
var lb = new String[] { "\r\n" };
var lines = txt_invoicenumber.Text.Split(lb, StringSplitOptions.None).Length;
This will count empty lines too. If you don't want to count empty lines, use the StringSplitOptions.RemoveEmptyEntries value.
Don't count 100% on "\r\n" if you have little control over your environment though.
This is the answer I came up with.
String[] lines = TextBox1.Text.Split(new Char[] { '\r', '\n' },
StringSplitOptions.RemoveEmptyEntries);
Int32 validLineCount = lines.Length;