How to find the index of a tuple element from an tuple array? iOS, Swift

问题

This is inside tableview cellforrowatindexpath

    var valueArray:[(String,String)] = []
    if !contains(valueArray, v: (title,status)) {
                let v = (title,status)
                valueArray.append(v)
            }

This is inside didselectrowatIndexPath

    let cell = self.tableView.cellForRowAtIndexPath(selectedRow!)
    var newTuple = (cell!.textLabel!.text!, cell!.detailTextLabel!.text!)
    let index = valueArray.indexOf(newTuple)

But i am not getting the index. It is throwing an error cannot convert value of type '(String,String)' to expected argument type '@noescape ((String,String)) throws -> Bool'. What i am doing wrong here?

回答1:

Tuples can be compared for equality (as of Swift 2.2/Xcode 7.3.1), but they do not conform to the Equatable protocol. Therefore you have to use the predicate-based variant of indexOf to locate a tuple in an array. Example:

let valueArray = [("a", "b"), ("c", "d")]
let tuple = ("c", "d")
if let index = valueArray.indexOf({ $0 == tuple }) {
    print("found at index", index)
}

In Swift 4 the method has been renamed to firstIndex(where:):

if let index = valueArray.firstIndex(where: { $0 == tuple }) {
    print("found at index", index)
}

回答2:

Here is my option to find index of tuples

var tuple: [(key: String, value: AnyObject)] = [("isSwap", true as AnyObject), ("price", 120 as AnyObject)]
if let index = tuple.index(where: {($0.key == "price")}) {
    print(index)
}
//prints 1

来源：https://stackoverflow.com/questions/37904601/how-to-find-the-index-of-a-tuple-element-from-an-tuple-array-ios-swift

标签

ios

arrays

swift

tuples