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indexOf abstract method
int indexOf(Returns the first index of element in this list.
Searches the list from index start to the end of the list. The first time an object o is encountered so that o == element, the index of o is returned.
List<String> notes = ['do', 're', 'mi', 're'];
notes.indexOf('re'); // 1
notes.indexOf('re', 2); // 3
Returns -1 if element is not found.
notes.indexOf('fa'); // -1
Source
int indexOf(E element, [int start = 0]);
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-core/List/indexOf.html