Question 76678 in Flutter Question posted in
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how to create an exception inside a flutter for loop

I need the items inside a for to have an action with the exception of the last one, which will have a different action

an example that DOESN’T WORK:

for (var i = 0; i < 10; i++) {
  print('1 - 9');


  if (i.last) {
    print('last item');
  }
}
Tags:

4

Answers


  1. 0

    Try this:

    for (var i = 0; i < 10; i++) {
  print('0 - 8');

  if (i == 9) {
    print('last item');
  }
}
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  2. 0

    you can try this

    for (var i = 0; i < 10; i++) {
 print('1 - 9');


 if (i==9) {
    print('last item');
    throw Exception("Your message");
 }
 }
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  3. 0

    This is also possible, you can just paste the snippet in DartPad and play with it

    void main() {
  try {
    for (var i = 0; i < 10; i++) {
      if (i == 3) {
        print('item $i');
        throw 'customError';
      } else {
        print('item $i');
      }
    }
  } catch (e) {
    if (e == 'customError') {
      print('You caught your custom error n $e');
    } else {
      print('You caught some other error');
    }
  }
}

    Hope that will help

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  4. 0

    You can put method in the condition part of the for loop. Here is such example:

    void main() {
  const limit = 10;
  for(int i =0 ;
      () {
        if(i < limit && i < limit-1) {
          doActionA(i);
          return true;
        }
        else if(i < limit){
          doActionB(i);
          return true;
        }
        return false;
      }()
      
      ; i++);
}

void doActionA(int i){
  print('Not last $i');
}

void doActionB(int i) {
  print('last $i');
}

    output

    Not last 0
Not last 1
Not last 2
Not last 3
Not last 4
Not last 5
Not last 6
Not last 7
Not last 8
last 9
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