How do I convert List into a String
How do I then use _checked string value in other place
List<String> _checked = [];
2 Answers
There are a bunch of ways. The first way is to simply call toString on the list:
final list = ['a', 'b', 'c'];
final str = list.toString();
// str = "[a, b, c]"
Another way is to use join, which will concatenate all the strings into a single string using an optional separator:
final list = ['a', 'b', 'c'];
final str = list.join('-');
// str = "a-b-c"
Other more specialized methods exist, but they require knowing more about what you want the output to look like.
3 Comments
Rishail Siddiqui
The instance member checked cannot be accessed in an initializer var checked=_checked.toString();
jamesdlin
@RishailSiddiqui Show what you're doing. Is
checked a normal variable? Is it a member variable? If it's a member variable, it matters where you're trying to initialize it.
Abion47
@RishailSiddiqui It sounds like you're trying to do something in a constructor's initializer list. You won't be able to do that with these methods, so put the code in the constructor body.
The join method is used for this. The array elements are converted to strings and then glued into one, in the arguments join you can pass a section that will be between the glued parts.
List<String> list = ["a", "b", "c"];
list.join() // 'abc';
list.join('|') // 'a|b|c'; // better for comparisons
Other way - use class:
import 'package:crypto/crypto.dart';
import 'package:convert/convert.dart';
import 'dart:convert';
class A {
List<String> a;
A(List<String> list): a = list;
@override
String toString() {
return a.join('|');
}
int get hashCode {
var bytes = utf8.encode(a.toString());
return md5.convert(bytes); a.toString().length;
//return a.toString().length; // silly hash
}
bool operator ==(other) {
String o = other.toString();
return (o == a.join('|'));
}
}
void main() {
A _checked = A(['1', '2', '3']);
A _other = A(['1', '2', '3']);
A _next = A(['12', '3']);
print(_checked == _other); // true
print(_checked); // 1|2|3
print(_checked == _next); // false
print(_next); // 12|3
}
Yes class is overkill, you can use just a function for the same:
String toString(List<String> a) {
return a.join('|');
}
print(toString(_checked) == toString(_other)); // true
print(toString(_checked)); // 1|2|3
print(toString(_checked) == toString(_next)); // false
print(toString(_next)); // 12|3
7 Comments
John Joe
Please write your answer in English.
Rishail Siddiqui
@Daniil The instance member checked cannot be accessed in an initializer var checked=_checked.toString()
Daniil Loban
_checked.toString() do you need it?
Abion47
The class method is such unbelievable overkill, and all it's doing is just calling
join anyway. How is it better or even as good as just calling join in the first place?Daniil Loban
@Abion47, yes, I add an another solution as a funtion
|
Stringvalue?