int indexOf(
E element,
[int start = 0]
)

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

/**
 * 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
 */
int indexOf(E element, [int start = 0]);