How to find index of a value from an array

Question

Suppose I am searching for cardType = points, if its found I want to know the index position of that object. According to the given example array, index position of this object is 1. Below is the example array.

[{
cardCode = MGC;
cardId = 5720663d8944bf6710c9d894;
cardType = gift;
},
{
cardCode = MPC;
cardId = 5720663d8944bf6710c9d898;
cardType = points;
}, 
{
cardCode = MAC;
cardId = 5720663d8944bf6710c9d895;
cardType = advantage;
},
{
cardCode = MCC;
cardId = 5720663d8944bf6710c9d897;
cardType = cashback;
}]

Both question are different. I not accecing the array which contain element of type String. The answer based on the method `index(of)` which is not available in my case. — Kunal Kumar, Mar 09 '17 at 12:48
Did you read *all* answers of that Q&A? http://stackoverflow.com/a/24069331/1187415 and http://stackoverflow.com/a/32923407/1187415 both explain how to use `index(where: ..)` — Martin R, Mar 09 '17 at 13:30

score 4 · Accepted Answer · answered Mar 09 '17 at 11:04

4

You can use index(where:) for that.

if let index = yourArray.index(where: { $0.cardType == "points" }) {
    print(index) //1
}

answered Mar 09 '17 at 11:04

Nirav D

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crashing with error message, found nil. But my array has the value. – Kunal Kumar Mar 09 '17 at 11:59
@KunalKumar Edit you question with your new code and add screen shot with error. – Nirav D Mar 09 '17 at 12:00
Everything is same as described in the question. – Kunal Kumar Mar 09 '17 at 12:05
@KunalKumar If it is all describe that you will not get nil. Where you are getting this nil? – Nirav D Mar 09 '17 at 12:08
something strange is happening, the line in question getting executed two times. first time it gives correct value, second time throwing error. – Kunal Kumar Mar 09 '17 at 12:17
@KunalKumar You are force wrapping your array, may be it is nil. try like this way `if let array = selectedCard, let index = array.index(where: { $0.cardType == "points" }) { print(index) //1 }` Also in question you have asked to compare for `points` and you are comparing `advantage` – Nirav D Mar 09 '17 at 12:25
Again same, don't know whats wrong. I think "points" or "advantage" is not the problem. It should have work with any – Kunal Kumar Mar 09 '17 at 12:34
btw selected card is an array or a dictionary ? if it is an array of dictionaries `if let index = arrayDict.index(where: { $0["cardType"] == "points" }) {` – Leo Dabus Mar 09 '17 at 12:45
@KunalKumar Can you add the declaration of `selectedCard` array? – Nirav D Mar 09 '17 at 12:47
selectedCard is array `var selectedCard:[AnyObject]?` Its getting populated with network response. – Kunal Kumar Mar 09 '17 at 12:50
@KunalKumar How does `AnyObject` have property `cardType`? – Nirav D Mar 09 '17 at 12:50
I think AnyObject can store any type of data. – Kunal Kumar Mar 09 '17 at 12:52
I am logging the selectedCard array to check if it has value or not. – Kunal Kumar Mar 09 '17 at 12:53
@KunalKumar Your `selectedCard` array contains dictionary as object or custom class object? – Nirav D Mar 09 '17 at 12:59
Dictionary as object – Kunal Kumar Mar 09 '17 at 13:00
Then try like this way `if let array = selectedCard, let index = array.index(where: { $0["cardType"] as? String ?? "" == "points" }) { print(index) //1 }` – Nirav D Mar 09 '17 at 13:02
worked :) can you update your answer with little explanation. – Kunal Kumar Mar 09 '17 at 13:07
@KunalKumar On of your dictionary in your array have nil value or key is not exist so that you are getting crash. – Nirav D Mar 09 '17 at 13:08

How to find index of a value from an array

1 Answers1