Dart find string value in a list using contains

Question

I have a list of numbers like below -

List contacts = [14169877890, 17781231234, 14161231234];

Now I want to find if one of the above list element would contain the below string value -

String value = '4169877890';

I have used list.any to do the search, but the below print statement inside the if condition is not printing anything.

if (contacts.any((e) => e.contains(value))) {
     print(contacts[0]);
}

I am expecting it to print out the first element of the contacts list as it partially contains the string value.

What is it I am doing wrong here?

Huthaifa Muayyad · Accepted Answer · 2022-04-27 03:30:35Z

3

Not sure if contacts is an integer and value is a string on purpose or mistake, but this works in dart pad if you convert it to string:

if (contacts.any((e) => e.toString().contains(value))) {
     print(contacts[0]);
}

DartPad Link.

answered Apr 27, 2022 at 3:30

Huthaifa Muayyad

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5 Comments

jamesdlin Over a year ago

You probably intend e.toString() == value. If you use contains, then '123' would be "found" in [1234].

Huthaifa Muayyad Over a year ago

I thought so, but Error: The method 'contains' isn't defined for the class 'int'.

jamesdlin Over a year ago

Huh? I'm telling you to not use contains.

Sumchans Over a year ago

So I made sure every single value in that list and list itself is a string. Also made sure the value I am searching for inside the list is also a string.

Sumchans Over a year ago

Finally found the issue, Thanks to all who helped figure it out.

Tuan · Accepted Answer · 2022-04-27 03:39:43Z

1

contacts isn't a List<String>, so your any search can't be true, you need turn element of contracts to string to able to use contains.

void main() {
  var contacts = [14169877890, 17781231234, 14161231234];
  print(contacts.runtimeType);
  var value = '4169877890';
  print(value.runtimeType);
  var haveAnyValid = contacts.any((element) {
    return "$element".contains(value);
  });
  print(haveAnyValid);
  
  // result

  // JSArray<int>
  // String
  // true
}

answered Apr 27, 2022 at 3:39

Tuan

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3 Comments

Sumchans Over a year ago

I checked the runtimetype, it says contacts is a dynamic list and those values are pulled in from an api call.

Tuan Over a year ago

If you make sure it is a List of String using type cast, or just use toString() or "$value" to turn them to String before use contacts

Sumchans Over a year ago

Yes I made it a list of strings, now I see the runtimetype as String. Still I haven't been able to make it work.

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